SketchComponent presetColors updating DOM improperly
Hello, 

Whenever I change a color using the Sketch color picker my preset colors get updated with a new array of colors based on the current palette. However it seems there's extra colors being added to the DOM whenever I change the color. The array I'm feeding in is correct and React picks up my new colors, but the DOM seems to have extra colors that aren't a part of the preset color array I feed in. I've attached photos of before and after. 

**Before**
![screen shot 2018-03-12 at 10 03 27 am](https://user-images.githubusercontent.com/9157341/37288215-1a24ad0e-25dd-11e8-8372-2d5c39b88520.png)
**After**
![screen shot 2018-03-12 at 10 03 37 am](https://user-images.githubusercontent.com/9157341/37288221-1e40b3ec-25dd-11e8-8796-10772063f71a.png)
