Add country names to provider details (bug 996085)


![compatibilit_et_paiements___test_app__hartebeest3204____marketplace_firefox](https://cloud.githubusercontent.com/assets/1514/2738599/6062d0b6-c691-11e3-80e2-f89736d97bec.png)

~~Getting the data felt clunky, I'm more than happy to take suggestions on improving that.~~ Moved to method in the model.

~~The display could use a few tweaks. I'll tidy that up tomorrow along with making the 'p' conditional.~~ Doesn't make sense that a provider won't have countries so that doesn't need to be conditional. Styling updated to be closer to the mock.