Refactored Callback system in osg::Node, osg::Drawable, osg::StateSet and osg::StateAttribute to use a new osg::Callback base class.

git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14244 16af8721-9629-0410-8352-f15c8da7e697

include/osgViewer/ViewerEventHandlers

@@ -525,7 +525,7 @@ protected:
     InteractiveImageHandler() {}
 
     InteractiveImageHandler(const InteractiveImageHandler&,const osg::CopyOp& = osg::CopyOp::SHALLOW_COPY):
-        osg::Object(), osgGA::GUIEventHandler(), osg::Drawable::CullCallback(), _fullscreen(false) {}
+        osg::Callback(), osgGA::GUIEventHandler(), osg::Drawable::CullCallback(), _fullscreen(false) {}
 
     bool mousePosition(osgViewer::View* view, osg::NodeVisitor* nv, const osgGA::GUIEventAdapter& ea, int& x, int &y) const;