Add 'Third' card size to facia-cards and style cutouts on them

Added the new third card. This extends the standard size along with any third specific styling (the first of which being cutouts).

I've also removed `.fc-item--half-mobile` as this class wasn't being created by scala isn't required.

Before:
![screen shot 2014-10-14 at 16 33 58](https://cloud.githubusercontent.com/assets/1607666/4631736/9aa1a442-53b7-11e4-909b-a9d19d349fa4.png)

After: 
![screen shot 2014-10-14 at 16 34 10](https://cloud.githubusercontent.com/assets/1607666/4631741/a0dd479e-53b7-11e4-8def-07a35f2ef8cd.png)