Adds list badges feature and view

I added a function to list badges so that viewers can see what they could earn through the system.

/bk/badges

![screen shot 2014-05-28 at 2 02 43 pm](https://cloud.githubusercontent.com/assets/2304883/3111175/0812729e-e6ae-11e3-870e-6922d92dfefd.png)