From Cedric Pinson, Traverse StripAction instead of applying, this fix the execution of FrameCallback in BlendIn, BlendOut and AnimationAction\nFix warning of osgAnimation::StatsHandler\nFix crash when running example osganimationtimeline without nathan.osg in OSG_FILE_PATH or with bad file

include/osgAnimation/Action

@@ -194,6 +194,8 @@ namespace osgAnimation
         void setLoop(unsigned int loop);
         void computeWeightAndUpdateAnimation(unsigned int frame);
 
+        void traverse(ActionVisitor& visitor);
+
     protected:
         typedef std::pair<unsigned int, osg::ref_ptr<BlendOut> > FrameBlendOut;
         osg::ref_ptr<BlendIn> _blendIn;