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
(force/torque sensor needs new API)
in a nutshell, users of shared memory physics API should not
directly poke into shared memory, not fill 'SharedMemorCommand'
nor read SharedMemoryStatus directly. The C-API declares 'handles' for those,
to avoid it from happening.