has_color() performance fixes

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.

win/share/safeproc.c

@@ -67,6 +67,7 @@
 
 struct window_procs safe_procs = {
     "safe-startup", 0L, 0L,
+    {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1},   /* color availability */
     safe_init_nhwindows, safe_player_selection, safe_askname, safe_get_nh_event,
     safe_exit_nhwindows, safe_suspend_nhwindows, safe_resume_nhwindows,
     safe_create_nhwindow, safe_clear_nhwindow, safe_display_nhwindow,