Cleanup calcCollisionsAll method

PHYS-16 #time 5m
Do collision detection/merging on calcForcesAll

PHYS-16 #time 15m

This prevents a second n^2 loop done only for the sake of detecting
merges. This behavior was one of the things preventing me from fully
benefitting from the octree.

Current problem: Some shapes seem to be getting improperly deleted after
a merge. Fix this ASAP.
Still trying to debug merging code

PHYS-16 #time 20m

This seems to be working fine in the nonrandom code, but I'm still
getting the weird behavior where both objects in a merge end up getting
eliminated when I try to run the generic bodyFormation code.

It seems that all the contact happens in pairs due to the way that I
"randomly" place objects. Deleting 2 objects at the end of the loops
might be causing the problem.