Work in progress refactoring ClickResolver.js to Ray.js

* Clickresolver.js: Implemented blackpawn's point in triangle algos ( http://www.blackpawn.com/texts/pointinpoly/default.html ). Now works properly with Face3 too.

* `CanvasRenderer` and `SVGRenderer` basic lighting support (`*ColorStroke`/`*ColorFill` only)
* `Renderer` > `Projector`. `CanvasRenderer`, `SVGRenderer` and `DOMRenderer` do not extend anymore
* Interactivity base code (hdi folder). To be refactored... ([mindlapse](http://github.com/mindlapse))
* Added `computeCentroids` method to `Geometry`
* Included `Stats.js` directly in the `/examples` folder to avoid the need of internet for playing around