Patch CZNC to allow an exit state into Loop().

Because unfortunately Csocket only supports select() and poll() on
Windows which are not altertable when a timeout is set,we have to go for
a very low timeout in the main loop. This way, an exit flag boolean can
be checked.
Disable color codes if ansicon is not available.
Implement Ctrl+C handler in ZNC_CLI.
Fix brace style in a few places.
Print message for Ctrl+C event.
Fix Csocket destruction in win32_service_helper.