Fix width on (large) user timeline

## Before:

![before](https://cloud.githubusercontent.com/assets/327237/4805337/abc5faf6-5e7b-11e4-9736-fb3c954c0dac.png)

## After:

![after](https://cloud.githubusercontent.com/assets/327237/4805341/b6f1daa8-5e7b-11e4-8034-f1254b7bb730.png)