Merge the "V3" message classes into the normal ones

We have no need for this abstraction so let's keep things simple.
diff --git a/common/rfb/TightEncoder.cxx b/common/rfb/TightEncoder.cxx
index 733365e..1cff7a6 100644
--- a/common/rfb/TightEncoder.cxx
+++ b/common/rfb/TightEncoder.cxx
@@ -18,6 +18,7 @@
  */
 #include <rdr/OutStream.h>
 #include <rfb/TransImageGetter.h>
+#include <rfb/PixelBuffer.h>
 #include <rfb/encodings.h>
 #include <rfb/ConnParams.h>
 #include <rfb/SMsgWriter.h>