Push encoder and decoder handling down into the connection objects

This keeps the reader and writer objects clean and simple protocol
decoders/encoders.
diff --git a/common/rfb/CMsgHandler.h b/common/rfb/CMsgHandler.h
index d7ffd65..8b58e0e 100644
--- a/common/rfb/CMsgHandler.h
+++ b/common/rfb/CMsgHandler.h
@@ -59,8 +59,7 @@
 
     virtual void framebufferUpdateStart() = 0;
     virtual void framebufferUpdateEnd() = 0;
-    virtual void beginRect(const Rect& r, int encoding) = 0;
-    virtual void endRect(const Rect& r, int encoding) = 0;
+    virtual void dataRect(const Rect& r, int encoding) = 0;
 
     virtual void setColourMapEntries(int firstColour, int nColours,
 				     rdr::U16* rgbs) = 0;