For the moment just things that are executed every frame in WebGLRenderer.render.

Continuing with quest to minimize creation of new data structures. Should instead create per class/object structures and just reuse them (as gman does in ThreeD). Main goal is to avoid annoying garbage collection pauses.

Let's hope it didn't break something (could be if some code was dependent on cloning of return values of "flatten" or "makeInvert3x3", though from what I checked these are just used to set typed arrays uniforms).