Ad width tablet

Due to recent changes in the way lists of links in columns work, scaling ads on tablet is now unnecessary.

### Before

![screen shot 2014-06-07 at 15 21 27](https://cloud.githubusercontent.com/assets/85783/3208957/b258cf52-ee4f-11e3-8855-ac356d4dd91d.PNG)


### After

![screen shot 2014-06-07 at 15 21 15](https://cloud.githubusercontent.com/assets/85783/3208958/b5a462ca-ee4f-11e3-9169-63b00591133d.PNG)

![ ](http://media.giphy.com/media/V1RYPjKiZeumk/giphy.gif)