Closes the connection to the dongle.
        
        Calls :meth:`reset` and then closes the serial port connection to the dongle.

def close(self):
        """Closes the connection to the dongle.
        
        Calls :meth:`reset` and then closes the serial port connection to the dongle."""
        logger.debug('closing dongle, {} active connections'.format(len(self.conn_handles)))
        if self.is_scanning():
            logger.debug('in scanning mode, calling end_scan')
            self.end_scan()
        self.reset()
        if self.api is not None:
            self.api.stop_daemon()
            self.api = None