Remove full support for colour maps

Gets rid of a loooot of code and complexity.

Colour map clients are still supported through an
automatically generated map, but we lose the ability to
develop a client or server that uses colour maps
internally.
diff --git a/win/rfb_win32/WMNotifier.h b/win/rfb_win32/WMNotifier.h
index a760964..ada45d0 100644
--- a/win/rfb_win32/WMNotifier.h
+++ b/win/rfb_win32/WMNotifier.h
@@ -44,7 +44,7 @@
 
       class Notifier {
       public:
-        typedef enum {DisplaySizeChanged, DisplayColourMapChanged,
+        typedef enum {DisplaySizeChanged,
           DisplayPixelFormatChanged} DisplayEventType;
         virtual void notifyDisplayEvent(DisplayEventType evt) = 0;
       };