Fix a matrix incorrectness I introduced
Use setZero
Initilialize BodyNode::mSkel = NULL and add assert to make sure it gets set before calling init
Move rendering into OpenGLRenderInterface

Functions such as BodyNode::draw() now have counterparts in
OpenGLRenderInterface. kinematics:: based draw() functions will be
removed in the future.
Merge branch 'master', remote-tracking branch 'origin' into eric/opengl-displaylists
Use colMesh argument in render's draw()
Clean OpenGLRenderInterface implementation
Fix col mesh rendering bug
Added CONTINUOUS JOINT and fixed addShape to save mass and inertia matrix, which only was sabed with addShapeMesh before