Kill the running process (if there is one)
        :return: void

def kill(self):
        """
        Kill the running process (if there is one)
        :return: void
        """
        if self.running():
            if self.verbose:
                print('Killing {} with PID {}'.format(self.exe, self.process.pid))
            self.process.kill()

            # Threads *should* tidy up after themselves, but we do it explicitly
            self.join_threads()