Styles the ngTagsInput

Dokku: https://tags-input-styles.dokku.hypothes.is

The editor sticks to our previous style, but I've styled it to wrap all the tags in the text area rather than having an input next to the tags, this pulls the whole thing together into a single field and looks much better.

![screen shot 2014-08-19 at 11 51 37](https://cloud.githubusercontent.com/assets/47144/3964238/72a9f640-2786-11e4-8127-872b8f7b0602.png)

As for the tags themselves, I've gone with just plain text rather than button styles. I felt the button styles in the read only annotations drew focus away from the text itself. By using text links here, they're less prominent but still work as they did before.

![screen shot 2014-08-19 at 11 51 16](https://cloud.githubusercontent.com/assets/47144/3964239/72aba332-2786-11e4-8646-3e3632b3b5fe.png)