Added releaseAllGLObjects() convinience method.

include/osgUtil/SceneView

@@ -414,6 +414,11 @@ class OSGUTIL_EXPORT SceneView : public osg::Referenced, public osg::CullSetting
         /** Do draw traversal of draw bins generated by cull traversal.*/
         virtual void draw();
         
+        /** Releast all OpenGL objects from the scene graph, such as texture objects, display lists etc.
+          * These released scene graphs placed in the respective delete GLObjects cache, which
+          * then need to be deleted in OpenGL by SceneView::flushAllDeleteGLObjects(). */
+        virtual void releaseAllGLObjects();
+
         /** Flush all deleted OpenGL objects, such as texture objects, display lists etc.*/
         virtual void flushAllDeletedGLObjects();