Numerical instability builds up with rotational motion

[BKaperick]

Even without considering collision mechanics, an object that is moving both translationally and rotationally suffers from consistent deformation as its corners drift away from each other.

This is likely due to some kind of bug or additionally some numerical instability in the rotational updating.

Can currently be seen by setting GLOBALROTSPEED in physics.py to a small constant such as 1.0.

[BKaperick]

In low speed rotations, we see squares degrading into trapezoids, and cyclically returning to their original form. With high speed rotations (on the order of 10 or 100 rotational velocity) we see extreme degradations at each collision event.