Use PAIR socket for slam, tidy up python stuff.

SlamController/slam_streamer.py

@@ -31,6 +31,10 @@ class SlamStreamer:
         to calling this method, and changing those values after
         calling this method will have no effect.
         '''
+        
+        # Block until user opens zmq.
+        self._socket.recv()
+
         # Adapted from BreezySLAM rpslam example.
         # Connect to Lidar unit
         lidar = Lidar(self._lidar_connection)
@@ -77,7 +81,7 @@ class SlamStreamer:
         return zmq.Context.instance()
 
     def _create_tcp_pub_socket(self):
-        return self._create_context().socket(zmq.PUB)
+        return self._create_context().socket(zmq.PAIR)
 
     def _start_socket(self, socket, port):
         socket.bind('tcp://*:' + str(self._port))