Override the command loop to handle Ctrl-C.

def cmdloop(self, intro=None):
        ''' Override the command loop to handle Ctrl-C. '''
        self.preloop()

        # Set up completion with readline.
        if self.use_rawinput and self.completekey:
            try:
                import readline
                self.old_completer = readline.get_completer()
                readline.set_completer(self.complete)
                readline.parse_and_bind(self.completekey + ': complete')
            except ImportError:
                pass

        try:
            if intro is not None:
                self.intro = intro
            if self.intro:
                self.stdout.write(str(self.intro)+"\n")
            stop = None
            while not stop:
                if self.cmdqueue:
                    line = self.cmdqueue.pop(0)
                else:
                    if self.use_rawinput:
                        try:
                            if sys.version_info[0] == 2:
                                line = raw_input(self.prompt)
                            else:
                                line = input(self.prompt)
                        except EOFError:
                            line = 'EOF'
                        except KeyboardInterrupt:
                            line = 'ctrlc'
                    else:
                        self.stdout.write(self.prompt)
                        self.stdout.flush()
                        line = self.stdin.readline()
                        if not len(line):
                            line = 'EOF'
                        else:
                            line = line.rstrip('\r\n')
                line = self.precmd(line)
                stop = self.onecmd(line)
                stop = self.postcmd(stop, line)
            self.postloop()
        finally:
            if self.use_rawinput and self.completekey:
                try:
                    import readline
                    readline.set_completer(self.old_completer)
                except ImportError:
                    pass