Updated to slideshow3D to support animation + pausing of animation.

Updated associated osg/osgUtil classes that provide animation pausing.

examples/slideshow3D/SlideEventHandler.h

@@ -77,6 +77,9 @@ protected:
     bool                        _autoSteppingActive;
     bool                        _loopPresentation;
     bool                        _pause;
+
+    void resetUpdateCallbacks();
+    void resetUpdateCallbackActivity();
         
 };