Improved color generation function

This trims the seed colors down and adds a generator function that provides mathematically optimally distant colors while always generating the same N colors for any N+1 set.

Translation: Shiny 

![screen shot 2014-12-10 at 3 42 15 pm](https://cloud.githubusercontent.com/assets/1250387/5385818/2c490280-8083-11e4-8f97-4910ec4f2d16.png)

I think you want `colors = seedColors.slice(0)` here