Mobile-friendly styles for licences

Additional CSS to target devices with small screen width. Also fixed a minor
config path typo in the readme.

I've not managed a great deal of testing of this across all licence versions and languages, but I'd welcome any feedback on the PR.

[Here's a screenshot from CC BY 4.0 en](https://cloud.githubusercontent.com/assets/80938/4836965/5eb21aee-5fcd-11e4-8143-aa5a80d95b75.png).