Add Bungie.net-style skin and move vault checkbox to header for space

Adds some css so the sidebar is not so glaring.  Also moves the Vault checkbox to allow better use of vertical space.

![upgrades_skinned](https://cloud.githubusercontent.com/assets/324189/4962216/95d699e6-66da-11e4-97cc-09aeae9e8b2f.png)

Doesn't 100% match Bungie.net's style, but it looks much nicer :smile: