Register SIGINT signal handler with the ioloop to cancel the currently running cmdloop task.

async def addSignalHandlers(self):
        '''
        Register SIGINT signal handler with the ioloop to cancel the currently running cmdloop task.
        '''

        def sigint():
            self.printf('<ctrl-c>')
            if self.cmdtask is not None:
                self.cmdtask.cancel()

        self.loop.add_signal_handler(signal.SIGINT, sigint)