Template: Improved `setState`: diff
Template: Improved `setState`: diff

When calling `setState` manually, it will now diff the new state with the old one. If there are differences, `onStateChanged` is called with the diff object passed along. The default behavior is to re-render itself.

MapKit/Fractal,tjoekbezoer/Fractal,tjoekbezoer/Fractal,MapKit/Fractal