Increase z-index of #start

Fixes the loading div being above the start box when unauthorized.

## Before

![screen shot 2013-12-07 at 3 29 33 pm](https://f.cloud.github.com/assets/282759/1699088/709fd69c-5f7e-11e3-9beb-d4f37505892d.png)

## After

![screen shot 2013-12-07 at 3 29 42 pm](https://f.cloud.github.com/assets/282759/1699089/720f6ad8-5f7e-11e3-9d06-3565d6a04435.png)