WIP pre-commit hook

This seems to work though I do not understand most of the magic in there – credits for that go to the linked sources.

What do you think?

(currently only checkes for .sass files. Would include other formats too before merge...)
There is no need to search for a config file because cli does that:
https://github.com/csscomb/csscomb.js/blob/master/lib/cli.js#L60
If it's launched with no `-c` parameter, it looks for custom config and if it can't find one, the default `csscomb.json` is used.