Match npm’s color scheme

I’ve made the colors match npm’s color scheme. It’s more consistent, but IMHO it looks better too.

Before:

![](https://cloud.githubusercontent.com/assets/81942/2788432/6ec51c2c-cb9b-11e3-9219-87d271169ddd.png)

After:

![](https://cloud.githubusercontent.com/assets/81942/2788420/4de7d22e-cb9b-11e3-9ba5-14a906010f81.png)

Note that I also added tests, so this patch closes #13.