Scale Slider

#186 #159

Styling is kind of buggy, but it's pretty straightforward to wire scale and rotate to the sliders.
![screen shot 2014-07-25 at 5 02 59 pm](https://cloud.githubusercontent.com/assets/6219591/3708158/2b7e3362-143f-11e4-9d41-e658be65665f.png)