Part of Bpy Cleanup: change attribute access to use tp_getset.

for these modules.  Adds some new convenience funcs to gen_utils.

This is internal change only and presents little change to the
BPy  API except for cleanup of some inconsistencies.

A big contribution from Ken Hughes.  Thanks!

source/blender/python/api2_2x/rgbTuple.h

@@ -51,6 +51,6 @@ typedef struct {
 /*****************************************************************************/
 PyObject *rgbTuple_New( float *rgb[3] );
 PyObject *rgbTuple_getCol( BPy_rgbTuple * self );
-PyObject *rgbTuple_setCol( BPy_rgbTuple * self, PyObject * args );
+int rgbTuple_setCol( BPy_rgbTuple * self, PyObject * args );
 
 #endif				/* EXPP_rgbTuple_H */