Commercial books refactor

Tweaking of layout to make sure that the books component follows the grids on fronts and articles across all possible break points.

Before;
![screen shot 2014-04-23 at 09 54 01](https://cloud.githubusercontent.com/assets/1303616/2775448/9bb4243e-cac5-11e3-9a29-db7fdc90f601.png)

After;
![screen shot 2014-04-23 at 09 54 19](https://cloud.githubusercontent.com/assets/1303616/2775452/a13347f0-cac5-11e3-9aff-edd28ea07bf9.png)