Changes for Help Modal to work on Stanford Site

- moved zendesk outside of theme condition
- improved help modal styling

Before:
![screen shot 2014-05-05 at 11 30 07 am](https://cloud.githubusercontent.com/assets/3364609/2882577/4320661e-d490-11e3-9d43-62a5b9725adb.png)

After:
![screen shot 2014-05-05 at 11 29 06 am](https://cloud.githubusercontent.com/assets/3364609/2882579/47ae3d64-d490-11e3-9747-fbb0da66c3b1.png)