Reposition comments

This moves comments to between the features and the most-popular components. We also alter the width of the comments presentation: 

Desktop: 

![signed-out-comments-wide](https://cloud.githubusercontent.com/assets/986155/2958933/0995eec2-daae-11e3-83fc-6b6be673dea1.png)

Tablet: 

![signed-out-comment-tablet](https://cloud.githubusercontent.com/assets/986155/2958940/1559b144-daae-11e3-9509-deb20ec04ed3.png)