Added tag register callbacks.

        logger.info('Successfully unregistered object %s', name)

    def rpc_tag_register_cb(self, call_id, response, error):

        pass

        name = self.async_calls.pop(call_id)

        if error is not None:

            logger.error('Error while trying to register tag %s, %s("%s")',

                         name, error['exception'], error['message'])

            return

        logger.debug('Successfully registered tag %s', name)

    def rpc_tag_unregister_cb(self, call_id, response, error):

        pass

        name = self.async_calls.pop(call_id)

        if error is not None:

            logger.error('Error while trying to unregister tag %s, %s("%s")',

                         name, error['exception'], error['message'])

            return

        logger.debug('Successfully unregistered tag %s', name)

    def rpc_sub_tag_register_cb(self, call_id, response, error):

        pass