Add license about css

[lencioni]

@backwardok that link is for a different repo. We should add one to this repo though.

[heldinz]

Thanks for adding this!

[DanielRuf]

It is probably licensed under the MIT license.

[DanielRuf]

See https://github.com/airbnb/javascript#license

[heldinz]

@DanielRuf I would hope that that is the case, but until a license is explicitly added to this repository, I have to consider it unlicensed.

[backwardok]

@heldinz are you looking for a particular file? The link that @DanielRuf provided is the license for this repo.

[backwardok]

oh hah! that's what I get for not paying attention to where I was posting :P too many repos

[lencioni]

Fixed by #63