Style contextual links

Drupal's contextual links have a 90% font size, causing them to appear differently depending where they are on the page:

![image](https://cloud.githubusercontent.com/assets/1784740/3186542/1d631030-eca4-11e3-9169-9bf64783cdf7.png)

This PR forces a consistent size, as well as integrating it with the theme a bit better (including changing the hover colour):

![image](https://cloud.githubusercontent.com/assets/1784740/3186558/524bb3b0-eca4-11e3-94b0-9c02441dd109.png)
![image](https://cloud.githubusercontent.com/assets/1784740/3186560/562b8b0e-eca4-11e3-9778-714873aa3537.png)