Addd high level introductory docs for all the libs

include/osgFX/Export

@@ -25,4 +25,14 @@
     #  define OSGFX_EXPORT
 #endif
 
+/**
+
+\namespace osgFX
+
+The osgFX is a NodeKit library that extends the core scene graph to provide a special effects framework. 
+osgFX's framework allows multiple rendering techniques to be provide for each effect, thereby provide the use
+appropriate rendering techniques for each different class of graphics hardware, i.e. support for both modern
+programmable graphics hardware and still have standard OpenGL 1.1 support as a fallback. 
+*/
+
 #endif