Writes the contents of the Rule to the logging system.

def log(self, level, prefix = ''):
        """Writes the contents of the Rule to the logging system.
        """
        logging.log(level, "%sin interface: %s", prefix, self.in_interface)
        logging.log(level, "%sout interface: %s", prefix, self.out_interface)
        logging.log(level, "%ssource: %s", prefix, self.source)
        logging.log(level, "%sdestination: %s", prefix, self.destination)
        logging.log(level, "%smatches:", prefix)
        for match in self.matches:
            match.log(level, prefix + '  ')
        if self.jump:
            logging.log(level, "%sjump:", prefix)
            self.jump.log(level, prefix + '  ')