Improved the doxygen docs over the various namespaces

include/osgIntrospection/Export

@@ -60,4 +60,12 @@ automatically generated by parsing header files via gen_wrapper utility.  All th
 core OpenSceneGraph libraries have pre built wrappers available for you use.
 */
 
+/**
+
+\namespace Properties
+
+Properties is a set of helper definations used by the osgIntrospectoin wrappers.
+
+*/
+
 #endif