Quadtree.js: Fixes, Docs

An update to quadtree.js that switches the call to jaws.collideOneWithMany with the simplified jaws.collide with a callback. It also now supports any object that has a forEach (both SpriteList and Array-like objects). There is also testing in the more public insert and retrieve functions.

There is also an expansion of all documentation from simple comments to full JSDocs format for each function.