Implement collisionFilterPlugin, use setCollisionFilterPair to enable or disable collision detection between specific pairs of objects.
Also, expose setCollisionFilterGroupMask as PyBullet API and in urdf using the tag <collision group="1" mask="2"/>.
See examples/pybullet/examples/collisionFilter.py for an example.
PyBullet default: Lower the warmstarting factor, for maximal coordinates rigid bodies for more stable simulation.
Add btCollisionWorld::refreshBroadphaseProxy to easier recreate the broadphase proxy without adding/removing objects to the world.
