From Cedric Pinson, this commit contains the following change:

* Change ref_ptr to observer_ptr to avoid cross reference and leak in Skinning
* Set invalidate to true to re run the check visitor in Skeleton
* Shallow copy Sampler in channel copy constructor
* Add accessor in VertexInfluence
* Remove dead code in Timeline.cpp
* Dont force linking in Bone::UpdateBone, the decision is done by the user or the manager
* Add offset in timeline stats to display each manager on the screen
* Add a flag in animation manager base to enable or not automatic link when modifying the manager

include/osgAnimation/AnimationManagerBase

@@ -44,18 +44,27 @@ namespace osgAnimation
         /** Callback method called by the NodeVisitor when visiting a node.*/
         virtual void operator()(osg::Node* node, osg::NodeVisitor* nv);
 
-        /// Operation that must be done each frame
+        /** Reset the value of targets
+            this Operation must be done each frame */
         void clearTargets();
+        
 
         LinkVisitor* getOrCreateLinkVisitor();
         void setLinkVisitor(LinkVisitor*);
 
+        /// set a flag to define the behaviour
+        void setAutomaticLink(bool);
+        bool isAutomaticLink() const;
+
+        void dirty();
+
     protected:
 
         osg::ref_ptr<LinkVisitor> _linker;
         AnimationList _animations;
         TargetSet _targets;
         bool _needToLink;
+        bool _automaticLink;
     };
 }
 #endif