Delete Point3D from scatter, delete dist3D and dist2D from scatter. Use

THREE.Vector3 whenever possible (it's tuned and faster and already in use in
these files).

Optimize fog and labels, Glove 40k sim + render went from ~13ms to ~4ms. Prefer dot product test for point visibility. Enable labels all the time now; they don't slow down the sim anymore.
Change: 132697603