Make county boundaries opaque

@ohsk: Merge this if you think it's the right direction.

Transparency county boundaries:
![screen shot 2014-07-24 at 3 03 33 am](https://cloud.githubusercontent.com/assets/326918/3684809/68cbccb4-1301-11e4-8091-43c1a6823d7b.png)

Opaque:
![screen shot 2014-07-24 at 3 04 39 am](https://cloud.githubusercontent.com/assets/326918/3684814/7011de6e-1301-11e4-83cb-bba9efb5d86e.png)

I think the latter's a step up.