Add preliminary GRPC server for PyBullet and BulletRobotics.

Will add GRPC client and PyBullet GRPC server plugin.
Will cover most/all SharedMemoryCommand/SharedMemoryStatus messages.
Run the server, then test using the pybullet_client.py

examples/SharedMemory/grpc/pybullet_client.py

@@ -0,0 +1,28 @@
+"""The Python implementation of the PyBullet GRPC client."""
+
+from __future__ import print_function
+
+import grpc
+
+import pybullet_pb2
+import pybullet_pb2_grpc
+
+
+def run():
+  channel = grpc.insecure_channel('localhost:50051')
+  stub = pybullet_pb2_grpc.PyBulletAPIStub(channel)
+  response = stub.SubmitCommand(pybullet_pb2.PyBulletCommand(loadUrdfCommand=pybullet_pb2.LoadUrdfCommand(urdfFileName="plane.urdf", initialPosition=pybullet_pb2.vec3(x=0,y=0,z=0), useMultiBody=False, useFixedBase=True, globalScaling=2, urdfFlags = 1)))
+  print("PyBullet client received: " , response.statusType)
+  print("URDF objectid =", response.urdfStatus.objectUniqueId)
+  
+	
+  response = stub.SubmitCommand(pybullet_pb2.PyBulletCommand(stepSimulationCommand=pybullet_pb2.StepSimulationCommand()))
+  print("PyBullet client received: " , response.statusType)
+  
+  
+  #response = stub.SubmitCommand(pybullet_pb2.PyBulletCommand(terminateServerCommand=pybullet_pb2.TerminateServerCommand()))
+  #print("PyBullet client received: " , response.statusType)
+
+
+if __name__ == '__main__':
+  run()