add rolling/spinning friction to cube, remove it from plane/samurai.urdf
URDF2Bullet: support joint limits for revolute and prismatic, only if defined (if upper < lower, disable limit)
add some profiling markers to improve performance
rolling friction -> only along the normal, until we have separate rolling friction coefficients on normal and non-normal directions
Don't teleport with grasping controller (VR)
Tune VR grasping a bit.