Upgrade to bootstrap 3

Before:
![image](https://f.cloud.github.com/assets/23801/2456808/13b93c98-af24-11e3-88f9-90dd5ce1c7cd.png)

After:
![image](https://f.cloud.github.com/assets/23801/2456806/0425f82a-af24-11e3-8c62-b61936ff9a7d.png)