Attempt some proper cleanup on shutdown

microservice.py

@@ -187,6 +187,12 @@ if __name__ == '__main__':
         debug=False
     )
 
+    print('Stopping any currently streaming radios...')
+    for radio in radios:
+      if radios[radio].is_streaming():
+        radios[radio].end_stream()
+    radios = None
+
     print('Killing RTSP relay...')
     rtsp_relay.kill()
     rtsp_relay.wait() # Necessary?