Allow label color selection

This may or may not be undesirable fluff, but it's a very small addition - the main usage case being varied label colour rather than a vast number of labels.

![labels](https://cloud.githubusercontent.com/assets/11458/4449706/5e0ebab4-481e-11e4-9772-4e93a1131808.png)

you can inline this with Array(label)