add first idea for the cli command set

[sternenseemann]

See also #72! Feel free to add other useful commands (for example for git deployment I havent used that feature yet).

[kingcons]

Overall, this looks good.

Also, if you want to make mention of Fukamachi's Shelly up above between buildapp and cl-launch, that would be welcome. :)

For the time being, I'd like to avoid having deployment handled in the cli commands. At least for a little while. Users have very different setups and that's why there are so many deploy plugins (Heroku, S3, Git/Versioned, etc). It may be something we can add later but I don't want it in the first version of Coleslaw CLI.

A few other changes I'd make:

• The --format option to post should be optional, it should default to md for markdown.
• It might be good to rename --dir to --repo-dir for clarity. I'd also prefer it default first to the :repo-dir in ~/.coleslawrc and then to ..

I think the initial command set should be: build, clean, rebuild, serve, post and maybe page for static pages.