Use different choropleth colors

@ohsk Does this look good?

Old:
![screen shot 2014-08-04 at 3 49 47 pm](https://cloud.githubusercontent.com/assets/326918/3802582/e925657e-1c10-11e4-9518-36945b39aa0f.png)


New:
![screen shot 2014-08-04 at 3 50 20 pm](https://cloud.githubusercontent.com/assets/326918/3802584/ede8e752-1c10-11e4-82e4-24c60f05cb85.png)