Tags Redux: styling tags

This PR styles the tags closer to what they were before we removed Jquery UI. Personally, I preferred them with some styling to show they were distinct from the annotation body. 
![tags](https://cloud.githubusercontent.com/assets/521978/4004591/9ce489f8-2983-11e4-9c1c-fe5d6ebc0c11.png)

Meant to resolve: https://github.com/hypothesis/h/issues/1426
Please avoid using element selectors where possible if there's a class name available use it.

https://smacss.com/book/type-module#avoid