I'm undecided about this change. Not sure if getObject* is better than getChild*.

Remove recursive calls from PolyhedronGeometry, replacing them with an
analytical construction of the geometry.

In unscientific studies, at high detail levels (> 5), this appears to yield
a ~30% reduction in runtime.

Base code by now...

Multiple objects can have the same id. Using that id to compare the render
objects makes the sort function unstable. Use the webgl object's index in the
render list instead. That number is guaranteed to be unique.

This fixes #2966.

Misteriously when using the latest version of the lib on the project I'm working on I'm getting this error:
> Uncaught TypeError: Object [object Object] has no method 'set'
This is caused when THREE.UniformsLib.common.diffuse initialises a THREE.Color (THREE.Color.set() seems to be undefined then).
For some reason this only happens when I load Box2D before three.js. If I load it after is all good. But this fixes the problem too.
/ping @bhouston