Tidy up lidar tracker and its protos

persontracking/lidar_servicer.py

@@ -1,27 +1,26 @@
 import persontracking.lidar_tracker_pb2 as lidar_tracker_pb2
 from persontracking.lidar_tracker_pb2_grpc import PersonTrackingServicer
-from persontracking.lidar_cache import LidarCache\
-
+from persontracking.lidar_cache import LidarCache
+from multiprocessing import Process
 
 
 class LidarServicer(PersonTrackingServicer):
+    lidar_thread = None
 
     def __init__(self):
         self.cache = LidarCache(measurements=100)
-        self.cache.do_scanning()
 
     def set_tracking_group(self, request, context):
         pass
 
     def stop_tracking(self, request, context):
         self.cache.stop_scanning()
-
-    def get_scan_data(self, request, context):
-        pass
+        self.lidar_thread.join()
+        self.lidar_thread = None
 
     def start_tracking(self, request, context):
         '''
         Starts the lidar cache. 
         '''
-        pass
-    
+        if self.lidar_thread is None:
+            self.lidar_thread = Process(target=self.cache.do_scanning)