Expose COV_ENABLE_VR_RENDER_CONTROLLERS, to enable/disable rendering of controllers (and some frames) in VR
Expose COV_ENABLE_RENDERING to enable/disable rendering.
Fix some multi-threading issues (potential crashes), related to debug drawing/rendering in one thread, while changing the dynamics world/removing/resetSimulation in a different thread.
add missing 1.sdf for Bullet/data/kitchens/1.sdf
add support for getting keyboard events (pybullet.getKeyboardEvents and b3RobotSimulatorClientAPI::getKeyboardEvents)
Change SHARED_MEMORY_MAGIC_NUMBER to make sure server/client are using the same version (shared memory)
add --realtimesimulation to physics server (GUI, VR)
remove --G Xcode from build_cmake_pybullet_double.sh
add UDP network connection for physics client <-> server.
also set spinning friction in rolling friction demo (otherwise objects may keep on spinning forever)