Fixes #565 - Cleanup Modal Popup 

Adds some styling for modal popups and custom select boxes based on the mock given in the issue description.

Mock: 

![screen shot 2013-09-08 at 11 20 23](https://f.cloud.github.com/assets/3777511/1102930/742ddd04-1870-11e3-9947-4ba25257a774.png)

Actual:

![screen shot 2013-09-08 at 11 20 59](https://f.cloud.github.com/assets/3777511/1102931/819a7da8-1870-11e3-83de-a141972d948e.png)