Style the 'no apps' message in the multi-app selector.

r? @ngokevin @spasovski

## Before:

![screen shot 2014-07-21 at 12 11 27 pm](https://cloud.githubusercontent.com/assets/23885/3647049/165c44a8-10fa-11e4-9efc-0c5251577dcf.png)

## After:

![screen shot 2014-07-21 at 12 11 13 pm](https://cloud.githubusercontent.com/assets/23885/3647054/20177d6e-10fa-11e4-96e9-a78f5889a6d1.png)