CLI: Search for a config file recursively (#68, 106)

Issues #68 and #106.

Check if there is a `.csscomb.json` file in process directory.
If not, go one level up and search there.
Stop in HOME dir.
If no user's config found, take a default one from our package: `config/csscomb.json`.

Any ideas about writing tests are welcome.

![tumblr_mvwp4uoyc91slo91to1_400](https://f.cloud.github.com/assets/872004/1592350/d329a09e-52b9-11e3-842c-6509c6d22495.gif)