Two callers of get_spendable_coins were removing frozen addrs
before calling. Put that functionality in the function.
We shouldn't be able to send_from a frozen address. This was
possible in the current release because logic assumed a two-element
tuple was returned when it is now three-element. Fix that too.
Command line options listunspent and createrawtransaction currently
ignore frozen addresses. I'm not sure that's right but I've preserved
that behaviour.
With this patch only the wallet class refers to self.frozen_addresses;
other clients use is_frozen() now.
Speedup mainly from writing to storage only once.
Make frozen_addresses a set in memory, as sets give cleaner
code and are more efficient.
Minor change in behaviour: command line freezing used to return
False if the address isn't in the wallet OR the address was already
frozen. Now it returns more like a success code: it returns False
only if the address isn't in the wallet regardless of frozen state.
Similarly for unfreezing.
Fees should be recalculated when send_from changes.
Fees should be recalculated when editing fee preference, but
only save to storage when leaving the fee per kb widget.
No need to emit a textEdited signal; the widget does that already
(with the effect that we used to call update_fee() twice).
Probably speeds it up by about a factor of two.
Unfortunately it needs to be another 5x faster
for sluggishness to disappear in the GUI when
typing a description in the receive tab.
Note the old code was off-by-one.