Introduce debug command

        self.printer.out(cccli.version)

class Command_debug(Command):

    '''Switch to debug mode'''

    def __call__(self, argv):

        if len(argv) != 1:

            raise cmdBadArgument()

        import cccli

        cccli.debug = not cccli.debug

class Command_whoami(Command):

    '''Show connection login'''