rigid: main finding is rigid needs to take delta into account for integration (aka interpolation)
also used POINT_EPSILON for thresholds for consistency
for rigidshape/item/player, main finding was length calcs for the search area were all over the place,
so we now derive the extended length of the cached area based on the velocity and the object's radius itself rather than guessin per class
atrest gravity calc suplimental syncing between rigidshape and vehicle
**remindernote POINT_EPSILO is 0.0001
First line is to ensure similar behavior to current regarding pushback on the object doing the colliding.
Second line applies an impulse to the rigid that was collided with.
