Support auto-resizing on rotations, fix #18

@bmnick Can you take a look? :smile_cat:

Here's a gif with color blender layers if you want to see it in action:
![Demo](http://i.imgur.com/EVlE7QT.gif)

Hi, I only have one comment for this.
If you're planning to go storyboard + autolayout with this component, this line will cause an infinite loop of layoutSubview and layoutTokensAndInput. That's because setting the frame will lead to a call to layoutSubview.
I've dealt with this by constructing another method (say layoutMySubview) without this line, and call it on layoutSubview instead.
Your thoughts?