Quick fix for cut-off navigation

The better alternative would be to have the "Back To Top" button fixed to the top, and the rest of the side nav scrolling.

The issue: 
![screen shot 2014-10-20 at 10 21 20 am](https://cloud.githubusercontent.com/assets/34726/4702610/69b62dc4-5864-11e4-9187-a96350acdf13.png)