Replace large timeout (1024*1024*1024) using real-time clock timeout (10 seconds default)

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

examples/SharedMemory/PhysicsServerExample.cpp

@@ -1153,6 +1153,12 @@ public:
 			gCreateDefaultRobotAssets = true;
 		}
 
+		if (args.CheckCmdLineFlag("realtimesimulation"))
+		{
+			//gEnableRealTimeSimVR = true;
+			m_physicsServer.enableRealTimeSimulation(true);
+		}
+
 		if (args.CheckCmdLineFlag("norobotassets"))
 		{
 			gCreateDefaultRobotAssets = false;