Use PAIR socket for slam, tidy up python stuff.

SlamController/slam_servicer.py

@@ -3,19 +3,21 @@ import slam_streamer as slam
 from threading import Thread
 
 class SlamServicer(SlamController_pb2_grpc.SlamControlServicer):
+    slam_thread = None
+    
     def __init__(self, lidar_connection):
         print('Servicer initialised')
         self.slam = slam.SlamStreamer(lidar_connection=lidar_connection)
 
     def start_map_streaming(self, request, context):
-        if not hasattr(self, 'slamThread'):
+        if self.slam_thread is None:
             # Don't bother creating and starting slam more than once.
             self.slam.port = request.port
             self.slam.map_pixels = request.map_size_pixels
             self.slam.map_meters = request.map_size_meters
-            slamThread = Thread(target=self.slam.start)
-            slamThread.start()
+            self.slam_thread = Thread(target=self.slam.start)
+            self.slam_thread.start()
 
     def stop_streaming(self, request, context):
-        if hasattr(self, 'slamThread'):
+        if self.slam_thread is not None:
             self.slam.stop_scanning()