Quad tree for collision detection

[maerch]

• Quad tree for efficient collision detection
• Shape class for extendable collision detection

[maryrosecook]

Does the (for example) Coquette.Collider.Shape.Rectangle need to be instantiated? Can it not be preinstantiated inside Coquette and then just assigned inside an entity as before eg:

javascript

Collider.prototype = {
//...
RECTANGLE: new this.Shape.Rectangle(),
CIRCLE: new this.Shape.Circle()
}

var Ball = function() {
this.boundingBox = Coquette.Collider.RECTANGLE;
};

To support this, `this` inside the `isIntersecting()` functions would need to be used.

[maryrosecook]

Thanks a lot for the PR! I've added a bunch of comments. Happy to discuss anytime.

[maerch]

Thanks for your suggestions. I have applied and pushed them.

[maryrosecook]

Thanks a lot for your edits. I'll take a look.