diff --git a/chrono_io/chrono_io b/chrono_io/chrono_io
deleted file mode 100644
index 8de9d4f45..000000000
--- a/chrono_io/chrono_io
+++ /dev/null
@@ -1,1140 +0,0 @@
-//  chrono_io
-//
-//  (C) Copyright Howard Hinnant
-//  Use, modification and distribution are subject to the Boost Software License,
-//  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
-//  http://www.boost.org/LICENSE_1_0.txt).
-
-#ifndef _CHRONO_IO
-#define _CHRONO_IO
-
-/*
-
-    chrono_io synopsis
-
-#include <chrono>
-#include <ratio_io>
-
-namespace std
-{
-namespace chrono
-{
-
-template <class CharT>
-class durationpunct
-    : public locale::facet
-{
-public:
-    static locale::id id;
-
-    typedef basic_string<CharT> string_type;
-    enum {use_long, use_short};
-
-    explicit durationpunct(int use = use_long);
-
-    durationpunct(int use,
-        const string_type& long_seconds, const string_type& long_minutes,
-        const string_type& long_hours, const string_type& short_seconds,
-        const string_type& short_minutes, const string_type& short_hours);
-
-    durationpunct(int use, const durationpunct& d);
-
-    template <class Period> string_type short_name() const;
-    template <class Period> string_type  long_name() const;
-    template <class Period> string_type       name() const;
-
-    bool is_short_name() const;
-    bool is_long_name() const;
-};
-
-template <class CharT, class Traits>
-    basic_ostream<CharT, Traits>&
-    duration_short(basic_ostream<CharT, Traits>& os);
-
-template <class CharT, class Traits>
-    basic_ostream<CharT, Traits>&
-    duration_long(basic_ostream<CharT, Traits>& os);
-
-template <class CharT, class Traits, class Rep, class Period>
-    basic_ostream<CharT, Traits>&
-    operator<<(basic_ostream<CharT, Traits>& os, const duration<Rep, Period>& d);
-
-template <class CharT, class Traits, class Rep, class Period>
-    basic_istream<CharT, Traits>&
-    operator>>(basic_istream<CharT, Traits>& is, duration<Rep, Period>& d);
-
-template <class CharT, class Traits, class Duration>
-    basic_ostream<CharT, Traits>&
-    operator<<(basic_ostream<CharT, Traits>& os,
-               const time_point<steady_clock, Duration>& tp);
-
-template <class CharT, class Traits, class Duration>
-    basic_ostream<CharT, Traits>&
-    operator<<(basic_ostream<CharT, Traits>& os,
-               const time_point<high_resolution_clock, Duration>& tp);
-
-template <class CharT, class Traits, class Duration>
-    basic_ostream<CharT, Traits>&
-    operator<<(basic_ostream<CharT, Traits>& os,
-               const time_point<system_clock, Duration>& tp);
-
-template <class CharT, class Traits, class Duration>
-    basic_istream<CharT, Traits>&
-    operator>>(basic_istream<CharT, Traits>& is,
-               time_point<steady_clock, Duration>& tp);
-
-template <class CharT, class Traits, class Duration>
-    basic_istream<CharT, Traits>&
-    operator>>(basic_istream<CharT, Traits>& is,
-               time_point<high_resolution_clock, Duration>& tp);
-
-template <class CharT, class Traits, class Duration>
-    basic_istream<CharT, Traits>&
-    operator>>(basic_istream<CharT, Traits>& is,
-               time_point<system_clock, Duration>& tp);
-
-template <class CharT>
-class timepunct
-    : public std::locale::facet
-{
-public:
-    typedef std::basic_string<CharT> string_type;
-
-    static std::locale::id id;
-
-    explicit timepunct(std::size_t refs = 0,
-                        const string_type& fmt = string_type(),
-                        bool local = false);
-
-    explicit timepunct(std::size_t refs,
-                        string_type&& fmt,
-                        bool local = false);
-
-    const string_type& fmt() const {return fmt_;}
-    bool             local() const {return local_;}
-};
-
-template<class CharT>
-    unspecfiied
-    local_fmt(std::basic_string<CharT> fmt = std::basic_string<CharT>());
-
-template<class CharT>
-    unspecfiied
-    local_fmt(const CharT* fmt);
-
-template<class CharT>
-    unspecfiied
-    utc_fmt(std::basic_string<CharT> fmt = std::basic_string<CharT>());
-
-template<class CharT>
-    unspecfiied
-    utc_fmt(const CharT* fmt);
-
-}  // chrono
-}  // std
-
-*/
-
-#include <chrono>
-#include "ratio_io"
-
-namespace std {
-
-namespace chrono
-{
-
-template <class To, class Rep, class Period>
-To
-round(const duration<Rep, Period>& d)
-{
-    To t0 = duration_cast<To>(d);
-    To t1 = t0;
-    ++t1;
-    typedef typename common_type<To, duration<Rep, Period> >::type _D;
-    _D diff0 = d - t0;
-    _D diff1 = t1 - d;
-    if (diff0 == diff1)
-    {
-        if (t0.count() & 1)
-            return t1;
-        return t0;
-    }
-    else if (diff0 < diff1)
-        return t0;
-    return t1;
-}
-
-template <class _CharT>
-class durationpunct
-    : public locale::facet
-{
-public:
-    typedef basic_string<_CharT> string_type;
-    enum {use_long, use_short};
-
-private:
-    bool __use_short_;
-    string_type __seconds_;
-    string_type __minutes_;
-    string_type __hours_;
-public:
-    static locale::id id;
-
-    explicit durationpunct(size_t refs = 0,
-                            int __use = use_long)
-        : locale::facet(refs), __use_short_(__use) {}
-
-    durationpunct(size_t refs, int __use,
-        string_type __seconds, string_type __minutes,
-        string_type __hours)
-        : locale::facet(refs), __use_short_(__use),
-          __seconds_(std::move(__seconds)),
-          __minutes_(std::move(__minutes)),
-          __hours_(std::move(__hours)) {}
-
-    bool is_short_name() const {return __use_short_;}
-    bool is_long_name() const {return !__use_short_;}
-
-    string_type seconds() const {return __seconds_;}
-    string_type minutes() const {return __minutes_;}
-    string_type hours() const {return __hours_;}
-};
-
-template <class _CharT>
-locale::id
-durationpunct<_CharT>::id;
-
-enum {prefix, symbol};
-enum {utc, local};
-
-template<class _CharT>
-struct __duration_manip
-{
-    bool __use_short_;
-    basic_string<_CharT> __seconds_;
-    basic_string<_CharT> __minutes_;
-    basic_string<_CharT> __hours_;
-
-    __duration_manip(bool __use_short, basic_string<_CharT> __seconds,
-                     basic_string<_CharT> __minutes, basic_string<_CharT> __hours)
-        : __use_short_(__use_short),
-          __seconds_(std::move(__seconds)),
-          __minutes_(std::move(__minutes)),
-          __hours_(std::move(__hours)) {}
-};
-
-class duration_fmt
-{
-    int form_;
-public:
-    explicit duration_fmt(int f) : form_(f) {}
-    // explicit
-        operator int() const {return form_;}
-};
-
-template<class charT, class traits>
-std::basic_ostream<charT, traits>&
-operator <<(std::basic_ostream<charT, traits>& os, duration_fmt d)
-{
-    os.imbue(std::locale(os.getloc(), new durationpunct<charT>(0, d == symbol)));
-    return os;
-}
-
-template<class charT, class traits>
-std::basic_istream<charT, traits>&
-operator >>(std::basic_istream<charT, traits>& is, duration_fmt d)
-{
-    is.imbue(std::locale(is.getloc(), new durationpunct<charT>(0, d == symbol)));
-    return is;
-}
-
-template<class charT, class traits>
-std::basic_ostream<charT, traits>&
-operator <<(std::basic_ostream<charT, traits>& os, __duration_manip<charT> m)
-{
-    os.imbue(std::locale(os.getloc(), new durationpunct<charT>(0, m.__use_short_,
-             std::move(m.__seconds_), std::move(m.__minutes_), std::move(m.__hours_))));
-    return os;
-}
-
-template<class charT, class traits>
-std::basic_istream<charT, traits>&
-operator >>(std::basic_istream<charT, traits>& is, __duration_manip<charT> m)
-{
-    is.imbue(std::locale(is.getloc(), new durationpunct<charT>(0, m.__use_short_,
-             std::move(m.__seconds_), std::move(m.__minutes_), std::move(m.__hours_))));
-    return is;
-}
-
-inline
-__duration_manip<char>
-duration_short()
-{
-    return __duration_manip<char>(durationpunct<char>::use_short, "", "", "");
-}
-
-template <class _CharT>
-inline
-__duration_manip<_CharT>
-duration_short(basic_string<_CharT> __seconds,
-               basic_string<_CharT> __minutes,
-               basic_string<_CharT> __hours)
-{
-    return __duration_manip<_CharT>(durationpunct<_CharT>::use_short,
-                                   std::move(__seconds), std::move(__minutes),
-                                   std::move(__hours));
-}
-
-inline
-__duration_manip<char>
-duration_long()
-{
-    return __duration_manip<char>(durationpunct<char>::use_long, "", "", "");
-}
-
-template <class _CharT, class _T2, class _T3>
-inline
-typename enable_if
-<
-    is_convertible<_T2, basic_string<_CharT> >::value &&
-    is_convertible<_T3, basic_string<_CharT> >::value,
-    __duration_manip<_CharT>
->::type
-duration_long(basic_string<_CharT> __seconds,
-              _T2 __minutes,
-              _T3 __hours)
-{
-    typedef basic_string<_CharT> string_type;
-    return __duration_manip<_CharT>(durationpunct<_CharT>::use_long,
-                                   std::move(__seconds),
-                                   string_type(std::move(__minutes)),
-                                   string_type(std::move(__hours)));
-}
-
-template <class _CharT, class _T2, class _T3>
-inline
-typename enable_if
-<
-    is_convertible<_T2, basic_string<_CharT> >::value &&
-    is_convertible<_T3, basic_string<_CharT> >::value,
-    __duration_manip<_CharT>
->::type
-duration_long(const _CharT* __seconds,
-              _T2 __minutes,
-              _T3 __hours)
-{
-    typedef basic_string<_CharT> string_type;
-    return __duration_manip<_CharT>(durationpunct<_CharT>::use_long,
-                                   string_type(__seconds),
-                                   string_type(std::move(__minutes)),
-                                   string_type(std::move(__hours)));
-}
-
-template <class _CharT, class _Period>
-basic_string<_CharT>
-__get_unit(bool __is_long, const basic_string<_CharT>& __seconds,
-           const basic_string<_CharT>&, const basic_string<_CharT>&, _Period)
-{
-    if (__is_long)
-    {
-        if (__seconds.empty())
-        {
-            _CharT __p[] = {'s', 'e', 'c', 'o', 'n', 'd', 's', 0};
-            return ratio_string<_Period, _CharT>::prefix() + __p;
-        }
-        return ratio_string<_Period, _CharT>::prefix() + __seconds;
-    }
-    if (__seconds.empty())
-        return ratio_string<_Period, _CharT>::symbol() + 's';
-    return ratio_string<_Period, _CharT>::symbol() + __seconds;
-}
-
-template <class _CharT>
-inline
-basic_string<_CharT>
-__get_unit(bool __is_long, const basic_string<_CharT>& __seconds,
-           const basic_string<_CharT>&, const basic_string<_CharT>&, ratio<1>)
-{
-    if (__seconds.empty())
-    {
-        if (__is_long)
-        {
-            _CharT __p[] = {'s', 'e', 'c', 'o', 'n', 'd', 's'};
-            return basic_string<_CharT>(__p, __p + sizeof(__p) / sizeof(_CharT));
-        }
-        else
-            return basic_string<_CharT>(1, 's');
-    }
-    return __seconds;
-}
-
-template <class _CharT>
-basic_string<_CharT>
-__get_unit(bool __is_long, const basic_string<_CharT>&,
-           const basic_string<_CharT>& __minutes,
-           const basic_string<_CharT>&, ratio<60>)
-{
-    if (__minutes.empty())
-    {
-        if (__is_long)
-        {
-            _CharT __p[] = {'m', 'i', 'n', 'u', 't', 'e', 's'};
-            return basic_string<_CharT>(__p, __p + sizeof(__p) / sizeof(_CharT));
-        }
-        else
-            return basic_string<_CharT>(1, 'm');
-    }
-    return __minutes;
-}
-
-template <class _CharT>
-inline
-basic_string<_CharT>
-__get_unit(bool __is_long, const basic_string<_CharT>&,
-           const basic_string<_CharT>&,
-           const basic_string<_CharT>& __hours, ratio<3600>)
-{
-    if (__hours.empty())
-    {
-        if (__is_long)
-        {
-            _CharT __p[] = {'h', 'o', 'u', 'r', 's'};
-            return basic_string<_CharT>(__p, __p + sizeof(__p) / sizeof(_CharT));
-        }
-        else
-            return basic_string<_CharT>(1, 'h');
-    }
-    return __hours;
-}
-
-template <class _CharT, class _Traits, class _Rep, class _Period>
-basic_ostream<_CharT, _Traits>&
-operator<<(basic_ostream<_CharT, _Traits>& __os, const duration<_Rep, _Period>& __d)
-{
-    typename basic_ostream<_CharT, _Traits>::sentry ok(__os);
-    if (ok)
-    {
-        typedef durationpunct<_CharT> _F;
-        typedef basic_string<_CharT> string_type;
-        bool failed = false;
-        try
-        {
-            bool __is_long = true;
-            string_type __seconds;
-            string_type __minutes;
-            string_type __hours;
-            locale __loc = __os.getloc();
-            if (has_facet<_F>(__loc))
-            {
-                const _F& f = use_facet<_F>(__loc);
-                __is_long = f.is_long_name();
-                __seconds = f.seconds();
-                __minutes = f.minutes();
-                __hours = f.hours();
-            }
-            string_type __unit = __get_unit(__is_long, __seconds, __minutes,
-                                            __hours, typename _Period::type());
-            __os << __d.count() << ' ' << __unit;
-        }
-        catch (...)
-        {
-            failed = true;
-        }
-        if (failed)
-            __os.setstate(ios_base::failbit | ios_base::badbit);
-    }
-    return __os;
-}
-
-template <class _Rep, bool = is_scalar<_Rep>::value>
-struct __duration_io_intermediate
-{
-    typedef _Rep type;
-};
-
-template <class _Rep>
-struct __duration_io_intermediate<_Rep, true>
-{
-    typedef typename conditional
-    <
-        is_floating_point<_Rep>::value,
-            long double,
-            typename conditional
-            <
-                is_signed<_Rep>::value,
-                    long long,
-                    unsigned long long
-            >::type
-    >::type type;
-};
-
-template <class T>
-T
-__gcd(T x, T y)
-{
-    while (y != 0)
-    {
-        T old_x = x;
-        x = y;
-        y = old_x % y;
-    }
-    return x;
-}
-
-template <>
-long double
-inline
-__gcd(long double x, long double y)
-{
-	(void)x;
-	(void)y;
-    return 1;
-}
-
-template <class _CharT, class _Traits, class _Rep, class _Period>
-basic_istream<_CharT, _Traits>&
-operator>>(basic_istream<_CharT, _Traits>& __is, duration<_Rep, _Period>& __d)
-{
-    typedef basic_string<_CharT> string_type;
-    typedef durationpunct<_CharT> _F;
-    typedef typename __duration_io_intermediate<_Rep>::type _IR;
-    _IR __r;
-    // read value into __r
-    __is >> __r;
-    if (__is.good())
-    {
-        // now determine unit
-        typedef istreambuf_iterator<_CharT, _Traits> _I;
-        _I __i(__is);
-        _I __e;
-        if (__i != __e && *__i == ' ')  // mandatory ' ' after value
-        {
-            ++__i;
-            if (__i != __e)
-            {
-                string_type __seconds;
-                string_type __minutes;
-                string_type __hours;
-                locale __loc = __is.getloc();
-                if (has_facet<_F>(__loc))
-                {
-                    const _F& f = use_facet<_F>(__loc);
-                    __seconds = f.seconds();
-                    __minutes = f.minutes();
-                    __hours = f.hours();
-                }
-                // unit is num / den (yet to be determined)
-                unsigned long long num = 0;
-                unsigned long long den = 0;
-                if (*__i == '[')
-                {
-                    // parse [N/D]s or [N/D]seconds format
-                    ++__i;
-                    _CharT __x;
-                    __is >> num >> __x >> den;
-                    if (!__is.good() || __x != '/')
-                    {
-                        __is.setstate(__is.failbit);
-                        return __is;
-                    }
-                    __i = _I(__is);
-                    if (*__i != ']')
-                    {
-                        __is.setstate(__is.failbit);
-                        return __is;
-                    }
-                    ++__i;
-                    const basic_string<_CharT> __units[] =
-                    {
-                        __get_unit(true, __seconds, __minutes, __hours, ratio<1>()),
-                        __get_unit(false, __seconds, __minutes, __hours, ratio<1>())
-                    };
-                    ios_base::iostate __err = ios_base::goodbit;
-                    const basic_string<_CharT>* __k = __scan_keyword(__i, __e,
-                                  __units, __units + sizeof(__units)/sizeof(__units[0]),
-                                  use_facet<ctype<_CharT> >(__loc),
-                                  __err);
-                    switch ((__k - __units) / 2)
-                    {
-                    case 0:
-                        break;
-                    default:
-                        __is.setstate(__err);
-                        return __is;
-                    }
-                }
-                else
-                {
-                    // parse SI name, short or long
-                    const basic_string<_CharT> __units[] =
-                    {
-                        __get_unit(true, __seconds, __minutes, __hours, atto()),
-                        __get_unit(false, __seconds, __minutes, __hours, atto()),
-                        __get_unit(true, __seconds, __minutes, __hours, femto()),
-                        __get_unit(false, __seconds, __minutes, __hours, femto()),
-                        __get_unit(true, __seconds, __minutes, __hours, pico()),
-                        __get_unit(false, __seconds, __minutes, __hours, pico()),
-                        __get_unit(true, __seconds, __minutes, __hours, nano()),
-                        __get_unit(false, __seconds, __minutes, __hours, nano()),
-                        __get_unit(true, __seconds, __minutes, __hours, micro()),
-                        __get_unit(false, __seconds, __minutes, __hours, micro()),
-                        __get_unit(true, __seconds, __minutes, __hours, milli()),
-                        __get_unit(false, __seconds, __minutes, __hours, milli()),
-                        __get_unit(true, __seconds, __minutes, __hours, centi()),
-                        __get_unit(false, __seconds, __minutes, __hours, centi()),
-                        __get_unit(true, __seconds, __minutes, __hours, deci()),
-                        __get_unit(false, __seconds, __minutes, __hours, deci()),
-                        __get_unit(true, __seconds, __minutes, __hours, deca()),
-                        __get_unit(false, __seconds, __minutes, __hours, deca()),
-                        __get_unit(true, __seconds, __minutes, __hours, hecto()),
-                        __get_unit(false, __seconds, __minutes, __hours, hecto()),
-                        __get_unit(true, __seconds, __minutes, __hours, kilo()),
-                        __get_unit(false, __seconds, __minutes, __hours, kilo()),
-                        __get_unit(true, __seconds, __minutes, __hours, mega()),
-                        __get_unit(false, __seconds, __minutes, __hours, mega()),
-                        __get_unit(true, __seconds, __minutes, __hours, giga()),
-                        __get_unit(false, __seconds, __minutes, __hours, giga()),
-                        __get_unit(true, __seconds, __minutes, __hours, tera()),
-                        __get_unit(false, __seconds, __minutes, __hours, tera()),
-                        __get_unit(true, __seconds, __minutes, __hours, peta()),
-                        __get_unit(false, __seconds, __minutes, __hours, peta()),
-                        __get_unit(true, __seconds, __minutes, __hours, exa()),
-                        __get_unit(false, __seconds, __minutes, __hours, exa()),
-                        __get_unit(true, __seconds, __minutes, __hours, ratio<1>()),
-                        __get_unit(false, __seconds, __minutes, __hours, ratio<1>()),
-                        __get_unit(true, __seconds, __minutes, __hours, ratio<60>()),
-                        __get_unit(false, __seconds, __minutes, __hours, ratio<60>()),
-                        __get_unit(true, __seconds, __minutes, __hours, ratio<3600>()),
-                        __get_unit(false, __seconds, __minutes, __hours, ratio<3600>())
-                    };
-                    ios_base::iostate __err = ios_base::goodbit;
-                    const basic_string<_CharT>* __k = __scan_keyword(__i, __e,
-                                  __units, __units + sizeof(__units)/sizeof(__units[0]),
-                                  use_facet<ctype<_CharT> >(__loc),
-                                  __err);
-                    switch ((__k - __units) / 2)
-                    {
-                    case 0:
-                        num = 1ULL;
-                        den = 1000000000000000000ULL;
-                        break;
-                    case 1:
-                        num = 1ULL;
-                        den = 1000000000000000ULL;
-                        break;
-                    case 2:
-                        num = 1ULL;
-                        den = 1000000000000ULL;
-                        break;
-                    case 3:
-                        num = 1ULL;
-                        den = 1000000000ULL;
-                        break;
-                    case 4:
-                        num = 1ULL;
-                        den = 1000000ULL;
-                        break;
-                    case 5:
-                        num = 1ULL;
-                        den = 1000ULL;
-                        break;
-                    case 6:
-                        num = 1ULL;
-                        den = 100ULL;
-                        break;
-                    case 7:
-                        num = 1ULL;
-                        den = 10ULL;
-                        break;
-                    case 8:
-                        num = 10ULL;
-                        den = 1ULL;
-                        break;
-                    case 9:
-                        num = 100ULL;
-                        den = 1ULL;
-                        break;
-                    case 10:
-                        num = 1000ULL;
-                        den = 1ULL;
-                        break;
-                    case 11:
-                        num = 1000000ULL;
-                        den = 1ULL;
-                        break;
-                    case 12:
-                        num = 1000000000ULL;
-                        den = 1ULL;
-                        break;
-                    case 13:
-                        num = 1000000000000ULL;
-                        den = 1ULL;
-                        break;
-                    case 14:
-                        num = 1000000000000000ULL;
-                        den = 1ULL;
-                        break;
-                    case 15:
-                        num = 1000000000000000000ULL;
-                        den = 1ULL;
-                        break;
-                    case 16:
-                        num = 1;
-                        den = 1;
-                        break;
-                    case 17:
-                        num = 60;
-                        den = 1;
-                        break;
-                    case 18:
-                        num = 3600;
-                        den = 1;
-                        break;
-                    default:
-                        __is.setstate(__err);
-                        return __is;
-                    }
-                }
-                // unit is num/den
-                // __r should be multiplied by (num/den) / _Period
-                // Reduce (num/den) / _Period to lowest terms
-                unsigned long long __gcd_n1_n2 = __gcd<unsigned long long>(num, _Period::num);
-                unsigned long long __gcd_d1_d2 = __gcd<unsigned long long>(den, _Period::den);
-                num /= __gcd_n1_n2;
-                den /= __gcd_d1_d2;
-                unsigned long long __n2 = _Period::num / __gcd_n1_n2;
-                unsigned long long __d2 = _Period::den / __gcd_d1_d2;
-                if (num > numeric_limits<unsigned long long>::max() / __d2 ||
-                    den > numeric_limits<unsigned long long>::max() / __n2)
-                {
-                    // (num/den) / _Period overflows
-                    __is.setstate(__is.failbit);
-                    return __is;
-                }
-                num *= __d2;
-                den *= __n2;
-                // num / den is now factor to multiply by __r
-                typedef typename common_type<_IR, unsigned long long>::type _CT;
-                if (is_integral<_IR>::value)
-                {
-                    // Reduce __r * num / den
-                    _CT __t = __gcd<_CT>(__r, den);
-                    __r /= __t;
-                    den /= __t;
-                    if (den != 1)
-                    {
-                        // Conversion to _Period is integral and not exact
-                        __is.setstate(__is.failbit);
-                        return __is;
-                    }
-                }
-                if (__r > duration_values<_CT>::max() / num)
-                {
-                    // Conversion to _Period overflowed
-                    __is.setstate(__is.failbit);
-                    return __is;
-                }
-                _CT __t = __r * num;
-                __t /= den;
-                if (duration_values<_Rep>::max() < __t)
-                {
-                    // Conversion to _Period overflowed
-                    __is.setstate(__is.failbit);
-                    return __is;
-                }
-                // Success!  Store it.
-                __r = _Rep(__t);
-                __d = duration<_Rep, _Period>(__r);
-            }
-            else
-                __is.setstate(__is.failbit | __is.eofbit);
-        }
-        else
-        {
-            if (__i == __e)
-                __is.setstate(__is.eofbit);
-            __is.setstate(__is.failbit);
-        }
-    }
-    else
-        __is.setstate(__is.failbit);
-    return __is;
-}
-
-template <class charT>
-class timepunct
-    : public std::locale::facet
-{
-public:
-    typedef std::basic_string<charT> string_type;
-
-private:
-    string_type fmt_;
-    bool        local_;
-
-public:
-    static std::locale::id id;
-
-    explicit timepunct(std::size_t refs = 0,
-                        const string_type& fmt = string_type(),
-                        bool local = false)
-        : std::locale::facet(refs),
-          fmt_(fmt),
-          local_(local) {}
-
-    explicit timepunct(std::size_t refs,
-                        string_type&& fmt,
-                        bool local = false)
-        : std::locale::facet(refs),
-          fmt_(std::move(fmt)),
-          local_(local) {}
-
-    const string_type& fmt() const {return fmt_;}
-    bool             local() const {return local_;}
-};
-
-template <class CharT>
-std::locale::id
-timepunct<CharT>::id;
-
-template <class _CharT, class _Traits, class _Duration>
-basic_ostream<_CharT, _Traits>&
-operator<<(basic_ostream<_CharT, _Traits>& __os,
-           const time_point<steady_clock, _Duration>& __tp)
-{
-    return __os << __tp.time_since_epoch() << " since boot";
-}
-
-template<class charT>
-struct __time_manip
-{
-    std::basic_string<charT> fmt_;
-    bool local_;
-
-    __time_manip(std::basic_string<charT> fmt, bool local)
-        : fmt_(std::move(fmt)),
-          local_(local) {}
-};
-
-template<class charT, class traits>
-std::basic_ostream<charT, traits>&
-operator <<(std::basic_ostream<charT, traits>& os, __time_manip<charT> m)
-{
-    os.imbue(std::locale(os.getloc(), new timepunct<charT>(0, std::move(m.fmt_), m.local_)));
-    return os;
-}
-
-template<class charT, class traits>
-std::basic_istream<charT, traits>&
-operator >>(std::basic_istream<charT, traits>& is, __time_manip<charT> m)
-{
-    is.imbue(std::locale(is.getloc(), new timepunct<charT>(0, std::move(m.fmt_), m.local_)));
-    return is;
-}
-
-template<class charT>
-inline
-__time_manip<charT>
-local_fmt(std::basic_string<charT> fmt)
-{
-    return __time_manip<charT>(std::move(fmt), true);
-}
-
-template<class charT>
-inline
-__time_manip<charT>
-local_fmt(const charT* fmt)
-{
-    return __time_manip<charT>(fmt, true);
-}
-
-inline
-__time_manip<char>
-local_fmt()
-{
-    return __time_manip<char>("", true);
-}
-
-template<class charT>
-inline
-__time_manip<charT>
-utc_fmt(std::basic_string<charT> fmt)
-{
-    return __time_manip<charT>(std::move(fmt), false);
-}
-
-template<class charT>
-inline
-__time_manip<charT>
-utc_fmt(const charT* fmt)
-{
-    return __time_manip<charT>(fmt, false);
-}
-
-inline
-__time_manip<char>
-utc_fmt()
-{
-    return __time_manip<char>("", false);
-}
-
-class __time_man
-{
-    int form_;
-public:
-    explicit __time_man(int f) : form_(f) {}
-    // explicit
-        operator int() const {return form_;}
-};
-
-template<class charT, class traits>
-std::basic_ostream<charT, traits>&
-operator <<(std::basic_ostream<charT, traits>& os, __time_man m)
-{
-    os.imbue(std::locale(os.getloc(), new timepunct<charT>(0, basic_string<charT>(), m == local)));
-    return os;
-}
-
-template<class charT, class traits>
-std::basic_istream<charT, traits>&
-operator >>(std::basic_istream<charT, traits>& is, __time_man m)
-{
-    is.imbue(std::locale(is.getloc(), new timepunct<charT>(0, basic_string<charT>(), m == local)));
-    return is;
-}
-
-
-inline
-__time_man
-time_fmt(int f)
-{
-    return __time_man(f);
-}
-
-template <class _CharT, class _Traits, class _Duration>
-basic_istream<_CharT, _Traits>&
-operator>>(basic_istream<_CharT, _Traits>& __is,
-           time_point<steady_clock, _Duration>& __tp)
-{
-    _Duration __d;
-    __is >> __d;
-    if (__is.good())
-    {
-        const _CharT __u[] = {' ', 's', 'i', 'n', 'c', 'e', ' ', 'b', 'o', 'o', 't'};
-        const basic_string<_CharT> __units(__u, __u + sizeof(__u)/sizeof(__u[0]));
-        ios_base::iostate __err = ios_base::goodbit;
-        typedef istreambuf_iterator<_CharT, _Traits> _I;
-        _I __i(__is);
-        _I __e;
-        ptrdiff_t __k = __scan_keyword(__i, __e,
-                      &__units, &__units + 1,
-                      use_facet<ctype<_CharT> >(__is.getloc()),
-                      __err) - &__units;
-        if (__k == 1)
-        {
-            // failed to read epoch string
-            __is.setstate(__err);
-            return __is;
-        }
-        __tp = time_point<steady_clock, _Duration>(__d);
-    }
-    else
-        __is.setstate(__is.failbit);
-    return __is;
-}
-
-template <class _CharT, class _Traits, class _Duration>
-basic_ostream<_CharT, _Traits>&
-operator<<(basic_ostream<_CharT, _Traits>& __os,
-           const time_point<system_clock, _Duration>& __tp)
-{
-    typename basic_ostream<_CharT, _Traits>::sentry ok(__os);
-    if (ok)
-    {
-        bool failed = false;
-        try
-        {
-            const _CharT* pb = nullptr;
-            const _CharT* pe = pb;
-            bool __local = false;
-            typedef timepunct<_CharT> F;
-            locale loc = __os.getloc();
-            if (has_facet<F>(loc))
-            {
-                const F& f = use_facet<F>(loc);
-                pb = f.fmt().data();
-                pe = pb + f.fmt().size();
-                __local = f.local();
-            }
-            time_t __t = system_clock::to_time_t(__tp);
-            tm __tm;
-            if (__local)
-            {
-                if (localtime_r(&__t, &__tm) == 0)
-                    failed = true;
-            }
-            else
-            {
-                if (gmtime_r(&__t, &__tm) == 0)
-                    failed = true;
-            }
-            if (!failed)
-            {
-                const time_put<_CharT>& tp = use_facet<time_put<_CharT> >(loc);
-                if (pb == pe)
-                {
-                    _CharT pattern[] = {'%', 'F', ' ', '%', 'H', ':', '%', 'M', ':'};
-                    pb = pattern;
-                    pe = pb + sizeof(pattern) / sizeof(_CharT);
-                    failed = tp.put(__os, __os, __os.fill(), &__tm, pb, pe).failed();
-                    if (!failed)
-                    {
-                        duration<double> __d = __tp - system_clock::from_time_t(__t) +
-                                  seconds(__tm.tm_sec);
-                        if (__d.count() < 10)
-                            __os << _CharT('0');
-                        ios::fmtflags __flgs = __os.flags();
-                        __os.setf(ios::fixed, ios::floatfield);
-                        __os << __d.count();
-                        __os.flags(__flgs);
-                        if (__local)
-                        {
-                            _CharT sub_pattern[] = {' ', '%', 'z'};
-                            pb = sub_pattern;
-                            pe = pb + + sizeof(sub_pattern) / sizeof(_CharT);
-                            failed = tp.put(__os, __os, __os.fill(), &__tm, pb, pe).failed();
-                        }
-                        else
-                        {
-                            _CharT sub_pattern[] = {' ', '+', '0', '0', '0', '0', 0};
-                            __os << sub_pattern;
-                        }
-                    }
-                }
-                else
-                    failed = tp.put(__os, __os, __os.fill(), &__tm, pb, pe).failed();
-            }
-        }
-        catch (...)
-        {
-            failed = true;
-        }
-        if (failed)
-            __os.setstate(ios_base::failbit | ios_base::badbit);
-    }
-    return __os;
-}
-
-template <class _CharT, class _Traits, class _Duration>
-basic_istream<_CharT, _Traits>&
-operator>>(basic_istream<_CharT, _Traits>& __is,
-           time_point<system_clock, _Duration>& __tp)
-{
-    typename basic_istream<_CharT,_Traits>::sentry ok(__is);
-    if (ok)
-    {
-        ios_base::iostate err = ios_base::goodbit;
-        try
-        {
-            const _CharT* pb = nullptr;
-            const _CharT* pe = pb;
-            bool __local = false;
-            typedef timepunct<_CharT> F;
-            locale loc = __is.getloc();
-            if (has_facet<F>(loc))
-            {
-                const F& f = use_facet<F>(loc);
-                pb = f.fmt().data();
-                pe = pb + f.fmt().size();
-                __local = f.local();
-            }
-            const time_get<_CharT>& tg = use_facet<time_get<_CharT> >(loc);
-            tm __tm = {0};
-            if (pb == pe)
-            {
-                _CharT pattern[] = {'%', 'Y', '-', '%', 'm', '-', '%', 'd',
-                                    ' ', '%', 'H', ':', '%', 'M', ':'};
-                pb = pattern;
-                pe = pb + sizeof(pattern) / sizeof(_CharT);
-                tg.get(__is, 0, __is, err, &__tm, pb, pe);
-                if (err & ios_base::failbit)
-                    goto __exit;
-                typedef istreambuf_iterator<_CharT, _Traits> _I;
-                double __sec;
-                _CharT __c = _CharT();
-                __is >> __sec;
-                if (__is.fail())
-                {
-                    err |= ios_base::failbit;
-                    goto __exit;
-                }
-                _I __i(__is);
-                _I __eof;
-                __c = *__i;
-                if (++__i == __eof || __c != ' ')
-                {
-                    err |= ios_base::failbit;
-                    goto __exit;
-                }
-                __c = *__i;
-                if (++__i == __eof || (__c != '+' && __c != '-'))
-                {
-                    err |= ios_base::failbit;
-                    goto __exit;
-                }
-                int __n = __c == '-' ? 1 : -1;
-                __c = *__i;
-                if (++__i == __eof || !isdigit(__c))
-                {
-                    err |= ios_base::failbit;
-                    goto __exit;
-                }
-                int __min = (__c - '0') * 600;
-                __c = *__i;
-                if (++__i == __eof || !isdigit(__c))
-                {
-                    err |= ios_base::failbit;
-                    goto __exit;
-                }
-                __min += (__c - '0') * 60;
-                __c = *__i;
-                if (++__i == __eof || !isdigit(__c))
-                {
-                    err |= ios_base::failbit;
-                    goto __exit;
-                }
-                __min += (__c - '0') * 10;
-                __c = *__i;
-                if (!isdigit(__c))
-                {
-                    err |= ios_base::failbit;
-                    goto __exit;
-                }
-                ++__i;
-                __min += __c - '0';
-                __min *= __n;
-                time_t __t;
-                __t = timegm(&__tm);
-                __tp = system_clock::from_time_t(__t) + minutes(__min)
-                                 + round<microseconds>(duration<double>(__sec));
-            }
-            else
-            {
-                tg.get(__is, 0, __is, err, &__tm, pb, pe);
-            }
-        }
-        catch (...)
-        {
-            err |= ios_base::badbit | ios_base::failbit;
-        }
-    __exit:
-        __is.setstate(err);
-    }
-    return __is;
-}
-
-}  // chrono
-
-}
-
-#endif  // _CHRONO_IO
diff --git a/chrono_io/ratio_io b/chrono_io/ratio_io
deleted file mode 100644
index ade52376c..000000000
--- a/chrono_io/ratio_io
+++ /dev/null
@@ -1,601 +0,0 @@
-//  ratio_io
-//
-//  (C) Copyright Howard Hinnant
-//  Use, modification and distribution are subject to the Boost Software License,
-//  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
-//  http://www.boost.org/LICENSE_1_0.txt).
-
-#ifndef _RATIO_IO
-#define _RATIO_IO
-
-/*
-
-    ratio_io synopsis
-
-#include <ratio>
-#include <string>
-
-namespace std
-{
-
-template <class Ratio, class charT>
-struct ratio_string
-{
-    static basic_string<charT> symbol();
-    static basic_string<charT> prefix();
-};
-
-}  // std
-
-*/
-
-#include <ratio>
-#include <string>
-#include <sstream>
-
-namespace  std {
-
-template <class _Ratio, class _CharT>
-struct ratio_string
-{
-    static basic_string<_CharT> symbol() {return prefix();}
-    static basic_string<_CharT> prefix();
-};
-
-template <class _Ratio, class _CharT>
-basic_string<_CharT>
-ratio_string<_Ratio, _CharT>::prefix()
-{
-    basic_ostringstream<_CharT> __os;
-    __os << _CharT('[') << _Ratio::num << _CharT('/')
-                        << _Ratio::den << _CharT(']');
-    return __os.str();
-}
-
-// atto
-
-template <>
-struct ratio_string<atto, char>
-{
-    static string symbol() {return string(1, 'a');}
-    static string prefix()  {return string("atto");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<atto, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'a');}
-    static u16string prefix()  {return u16string(u"atto");}
-};
-
-template <>
-struct ratio_string<atto, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'a');}
-    static u32string prefix()  {return u32string(U"atto");}
-};
-
-#endif
-
-template <>
-struct ratio_string<atto, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'a');}
-    static wstring prefix()  {return wstring(L"atto");}
-};
-
-// femto
-
-template <>
-struct ratio_string<femto, char>
-{
-    static string symbol() {return string(1, 'f');}
-    static string prefix()  {return string("femto");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<femto, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'f');}
-    static u16string prefix()  {return u16string(u"femto");}
-};
-
-template <>
-struct ratio_string<femto, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'f');}
-    static u32string prefix()  {return u32string(U"femto");}
-};
-
-#endif
-
-template <>
-struct ratio_string<femto, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'f');}
-    static wstring prefix()  {return wstring(L"femto");}
-};
-
-// pico
-
-template <>
-struct ratio_string<pico, char>
-{
-    static string symbol() {return string(1, 'p');}
-    static string prefix()  {return string("pico");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<pico, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'p');}
-    static u16string prefix()  {return u16string(u"pico");}
-};
-
-template <>
-struct ratio_string<pico, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'p');}
-    static u32string prefix()  {return u32string(U"pico");}
-};
-
-#endif
-
-template <>
-struct ratio_string<pico, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'p');}
-    static wstring prefix()  {return wstring(L"pico");}
-};
-
-// nano
-
-template <>
-struct ratio_string<nano, char>
-{
-    static string symbol() {return string(1, 'n');}
-    static string prefix()  {return string("nano");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<nano, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'n');}
-    static u16string prefix()  {return u16string(u"nano");}
-};
-
-template <>
-struct ratio_string<nano, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'n');}
-    static u32string prefix()  {return u32string(U"nano");}
-};
-
-#endif
-
-template <>
-struct ratio_string<nano, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'n');}
-    static wstring prefix()  {return wstring(L"nano");}
-};
-
-// micro
-
-template <>
-struct ratio_string<micro, char>
-{
-    static string symbol() {return string("\xC2\xB5");}
-    static string prefix()  {return string("micro");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<micro, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'\xB5');}
-    static u16string prefix()  {return u16string(u"micro");}
-};
-
-template <>
-struct ratio_string<micro, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'\xB5');}
-    static u32string prefix()  {return u32string(U"micro");}
-};
-
-#endif
-
-template <>
-struct ratio_string<micro, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'\xB5');}
-    static wstring prefix()  {return wstring(L"micro");}
-};
-
-// milli
-
-template <>
-struct ratio_string<milli, char>
-{
-    static string symbol() {return string(1, 'm');}
-    static string prefix()  {return string("milli");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<milli, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'm');}
-    static u16string prefix()  {return u16string(u"milli");}
-};
-
-template <>
-struct ratio_string<milli, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'm');}
-    static u32string prefix()  {return u32string(U"milli");}
-};
-
-#endif
-
-template <>
-struct ratio_string<milli, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'm');}
-    static wstring prefix()  {return wstring(L"milli");}
-};
-
-// centi
-
-template <>
-struct ratio_string<centi, char>
-{
-    static string symbol() {return string(1, 'c');}
-    static string prefix()  {return string("centi");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<centi, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'c');}
-    static u16string prefix()  {return u16string(u"centi");}
-};
-
-template <>
-struct ratio_string<centi, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'c');}
-    static u32string prefix()  {return u32string(U"centi");}
-};
-
-#endif
-
-template <>
-struct ratio_string<centi, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'c');}
-    static wstring prefix()  {return wstring(L"centi");}
-};
-
-// deci
-
-template <>
-struct ratio_string<deci, char>
-{
-    static string symbol() {return string(1, 'd');}
-    static string prefix()  {return string("deci");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<deci, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'd');}
-    static u16string prefix()  {return u16string(u"deci");}
-};
-
-template <>
-struct ratio_string<deci, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'd');}
-    static u32string prefix()  {return u32string(U"deci");}
-};
-
-#endif
-
-template <>
-struct ratio_string<deci, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'd');}
-    static wstring prefix()  {return wstring(L"deci");}
-};
-
-// deca
-
-template <>
-struct ratio_string<deca, char>
-{
-    static string symbol() {return string("da");}
-    static string prefix()  {return string("deca");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<deca, char16_t>
-{
-    static u16string symbol() {return u16string(u"da");}
-    static u16string prefix()  {return u16string(u"deca");}
-};
-
-template <>
-struct ratio_string<deca, char32_t>
-{
-    static u32string symbol() {return u32string(U"da");}
-    static u32string prefix()  {return u32string(U"deca");}
-};
-
-#endif
-
-template <>
-struct ratio_string<deca, wchar_t>
-{
-    static wstring symbol() {return wstring(L"da");}
-    static wstring prefix()  {return wstring(L"deca");}
-};
-
-// hecto
-
-template <>
-struct ratio_string<hecto, char>
-{
-    static string symbol() {return string(1, 'h');}
-    static string prefix()  {return string("hecto");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<hecto, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'h');}
-    static u16string prefix()  {return u16string(u"hecto");}
-};
-
-template <>
-struct ratio_string<hecto, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'h');}
-    static u32string prefix()  {return u32string(U"hecto");}
-};
-
-#endif
-
-template <>
-struct ratio_string<hecto, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'h');}
-    static wstring prefix()  {return wstring(L"hecto");}
-};
-
-// kilo
-
-template <>
-struct ratio_string<kilo, char>
-{
-    static string symbol() {return string(1, 'k');}
-    static string prefix()  {return string("kilo");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<kilo, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'k');}
-    static u16string prefix()  {return u16string(u"kilo");}
-};
-
-template <>
-struct ratio_string<kilo, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'k');}
-    static u32string prefix()  {return u32string(U"kilo");}
-};
-
-#endif
-
-template <>
-struct ratio_string<kilo, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'k');}
-    static wstring prefix()  {return wstring(L"kilo");}
-};
-
-// mega
-
-template <>
-struct ratio_string<mega, char>
-{
-    static string symbol() {return string(1, 'M');}
-    static string prefix()  {return string("mega");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<mega, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'M');}
-    static u16string prefix()  {return u16string(u"mega");}
-};
-
-template <>
-struct ratio_string<mega, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'M');}
-    static u32string prefix()  {return u32string(U"mega");}
-};
-
-#endif
-
-template <>
-struct ratio_string<mega, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'M');}
-    static wstring prefix()  {return wstring(L"mega");}
-};
-
-// giga
-
-template <>
-struct ratio_string<giga, char>
-{
-    static string symbol() {return string(1, 'G');}
-    static string prefix()  {return string("giga");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<giga, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'G');}
-    static u16string prefix()  {return u16string(u"giga");}
-};
-
-template <>
-struct ratio_string<giga, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'G');}
-    static u32string prefix()  {return u32string(U"giga");}
-};
-
-#endif
-
-template <>
-struct ratio_string<giga, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'G');}
-    static wstring prefix()  {return wstring(L"giga");}
-};
-
-// tera
-
-template <>
-struct ratio_string<tera, char>
-{
-    static string symbol() {return string(1, 'T');}
-    static string prefix()  {return string("tera");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<tera, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'T');}
-    static u16string prefix()  {return u16string(u"tera");}
-};
-
-template <>
-struct ratio_string<tera, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'T');}
-    static u32string prefix()  {return u32string(U"tera");}
-};
-
-#endif
-
-template <>
-struct ratio_string<tera, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'T');}
-    static wstring prefix()  {return wstring(L"tera");}
-};
-
-// peta
-
-template <>
-struct ratio_string<peta, char>
-{
-    static string symbol() {return string(1, 'P');}
-    static string prefix()  {return string("peta");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<peta, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'P');}
-    static u16string prefix()  {return u16string(u"peta");}
-};
-
-template <>
-struct ratio_string<peta, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'P');}
-    static u32string prefix()  {return u32string(U"peta");}
-};
-
-#endif
-
-template <>
-struct ratio_string<peta, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'P');}
-    static wstring prefix()  {return wstring(L"peta");}
-};
-
-// exa
-
-template <>
-struct ratio_string<exa, char>
-{
-    static string symbol() {return string(1, 'E');}
-    static string prefix()  {return string("exa");}
-};
-
-#if HAS_UNICODE_SUPPORT
-
-template <>
-struct ratio_string<exa, char16_t>
-{
-    static u16string symbol() {return u16string(1, u'E');}
-    static u16string prefix()  {return u16string(u"exa");}
-};
-
-template <>
-struct ratio_string<exa, char32_t>
-{
-    static u32string symbol() {return u32string(1, U'E');}
-    static u32string prefix()  {return u32string(U"exa");}
-};
-
-#endif
-
-template <>
-struct ratio_string<exa, wchar_t>
-{
-    static wstring symbol() {return wstring(1, L'E');}
-    static wstring prefix()  {return wstring(L"exa");}
-};
-
-}
-
-#endif  // _RATIO_IO
diff --git a/libdevcore/CommonIO.h b/libdevcore/CommonIO.h
index 2d0889bac..f42f449bb 100644
--- a/libdevcore/CommonIO.h
+++ b/libdevcore/CommonIO.h
@@ -36,7 +36,6 @@
 #include <string>
 #include <iostream>
 #include <chrono>
-#include <boost/chrono/chrono_io.hpp>
 #include "Common.h"
 #include "Base64.h"