Make build reports more readable

This patch adds a bit of styling to make reports nicer to look at.

Before:

* http://i.imgur.com/rD3qRjt.png
* http://i.imgur.com/8WqU6Id.png

After:

* http://i.imgur.com/FzHVAD4.png
* http://i.imgur.com/Vqj7kHX.png