allow 'useMaximalCoordinates' and 'useFixedBase' in pybullet.loadURDF. enable split impulse for btRigidBody, even in btMultiBodyDynamicsWorld. allow initialization of velocity and apply force for btRigidBody in pybullet/shared memory API. process contact parameters in URDF also for btRigidBody (friction, restitution etc) add pybullet.setPhysicsEngineParameter with numSolverIterations, useSplitImpulse etc.