Create a fallback for facia-cards images when headline is too long

Because I'm an idiot who didn't push something to our facia-cards-2.0 branch, this is in a separate PR.

This changes the colour behind the image dependant on tone. Which means when the headline is too long it looks like this...

![screen shot 2014-09-19 at 17 53 55](https://cloud.githubusercontent.com/assets/1607666/4338874/9a4786fe-401d-11e4-900b-115767353b3d.png)
ditto