Add M-x option

This is another way of utilizing prefix command.
Although I'm not sure everyone often do `M-2` or `C-u 2` before execute any command.
If this addition doesn't make any trouble, please merge it.

Example.
```
(defun mykie-M-number-test ()
  (interactive)
  (mykie
   :default            '(message "default")
   :M-1                '(message "M number 1")
   :M-2                '(message "M number 2")
   :M-3                '(message "M number 3")
   :M-12               '(message "M number 12")
   :C-u                '(message "C-u 1 time")
   :C-u*2              '(message "C-u 2 time")
   ))
(global-set-key (kbd "M-o") 'mykie-M-number-test)
```