Made update, cull and draw callbacks virtual to allow custom Drawable's to there own specific extensions for handling callbacks
Made update, cull and draw callbacks virtual to allow custom Drawable's
to there own specific extensions for handling callbacks


git-svn-id: 23b6355f2bb369032457de4eb5f713ee134f73a8@3399 16af8721-9629-0410-8352-f15c8da7e697

joevandyk/osg,joevandyk/osg,joevandyk/osg,joevandyk/osg,joevandyk/osg