support kinematic chains where joint are not part of the body rns

rbdl wrapper supports now multiple bodies between joints (inertina combination is untested; uses rbdl code to combine

* CoinVisualizationNode::scale
* TriMeshModel::scale
* VisualizationNode::scale

* It is possible to only close for n steps
* It is possible to provide a second larger step size to speed up closing / opening