Menu redesign

The old menu was getting pretty ugly so I redesigned it so that it is hierarchical and opens on hovering. I've attached a screenshot of what it looks like now.

![screen shot 2013-08-09 at 3 36 18 pm](https://f.cloud.github.com/assets/930642/941091/60db2bda-013c-11e3-87dc-1c0a0dcff966.png)