- adding ethash_io_write() function
- only ethash_io_prepare() invoke system dependent functions so it's the
only one going in system specific source files.
- DAG and memo file creation will now be taken care of in libethash
itself.
- To that end we crete a very minimal IO module for ethash.
- Depending on the target system io_posix or io_win32 will be used.
- Implemented ethash_io_prepare() for posix
Lefteris Karapetsas