New style for most read component

New wider breakpoint styling for the most read component at the bottom of content pages, as per Chris Pearson's design.

### Tablet
![screenshot from 2013-12-05 09 12 20](https://f.cloud.github.com/assets/80089/1681164/940993f4-5d8d-11e3-9a01-f85021d35024.png)


### Desktop
![screenshot from 2013-12-05 09 11 55](https://f.cloud.github.com/assets/80089/1681167/9b8e5b1e-5d8d-11e3-9b31-0ff8a261534d.png)


Thanks to @kaelig for his mad CSS skilllzzzzz!

![CSS](http://img.pandawhale.com/post-18529-Yes-mlkshk-1nAi.gif)