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/common/rfb/SMsgWriter.h b/common/rfb/SMsgWriter.h
index 5d45411..ee59eb3 100644
--- a/common/rfb/SMsgWriter.h
+++ b/common/rfb/SMsgWriter.h
@@ -33,7 +33,6 @@
 
   class ConnParams;
   class TransImageGetter;
-  class ColourMap;
   class Region;
   class UpdateInfo;
   class Encoder;
@@ -56,10 +55,11 @@
     // Methods to write normal protocol messages
 
     // writeSetColourMapEntries() writes a setColourMapEntries message, using
-    // the given ColourMap object to lookup the RGB values of the given range
-    // of colours.
+    // the given colour entries.
     void writeSetColourMapEntries(int firstColour, int nColours,
-                                  ColourMap* cm);
+                                  const rdr::U16 red[],
+                                  const rdr::U16 green[],
+                                  const rdr::U16 blue[]);
 
     // writeBell() and writeServerCutText() do the obvious thing.
     void writeBell();