* 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
Finally, I have fixed TemplateTarget<osg::Quat>::lerp() as it was giving incorrect results when interpolating between some small rotations.
From Cedric Pinson, i renamed the method in channel to be more general. Adjusted the CubicBezier key constructor to use a single value as input.
