Performance profiling showed that multiple strcmpi() calls were
occurring each and every time a character was going to the map.
This update:
- honors the WC_COLOR capability
- It allows a window-port to control individual color availability should the window-port wish to do so.
- Makes checking on the individual colors for the active window-port is a straightforward table lookup at the CLR_ offset.
iflags.use_color remains a master on/off switch for use of color, regardless of the capability
compiled into the game (default TRUE).
The has_color() routine, which is now a shared routine in src/windows.c, could likely be made
into a simple macro to eliminate the function call, but this update does not go that far.
This hits a lot of port files due to the window-port interface change, mostly cookie-cutter.
