Add a message id to the received messages

__init__.py

         logger.warning("Disconnect with rc=%s", repr(rc))
 
     def __receive__(self, client, userdata, message):
+        message.mid = self.__client__._mid_generate()	# add a message id to the received message
         get_topic_logger(message.topic).debug("Received message with topic %s and payload %s", message.topic, str(message.payload))
         for topic in self.__callbacks__.copy():
             if topic.endswith('#'):