Increase padding on comments, include user avatars

This makes comments a little nicer to look at.

### Before:
![screen shot 2014-11-13 at 00 44 41](https://cloud.githubusercontent.com/assets/432189/5021519/8eed5e06-6ace-11e4-9cda-6804d93d9ad1.png)

### After:
![screen shot 2014-11-13 at 00 45 17](https://cloud.githubusercontent.com/assets/432189/5021520/8ef21c16-6ace-11e4-9bb3-e95770992054.png)