Physics: Return deltas

[davesmith00000]

Could we return the rate of change of various properties, particularly velocity and position?

The use case is that for visual presentation reasons, it can be useful to know how a Collider moved last.

[davesmith00000]

This would be nice to do, but is a little fiddly.

Couple of options:

1. Colliders store their deltas, bit odd perhaps.
2. The world has a separate update method that providers a wrapper with additional metadata per object, like deltas and maybe what it collided with.

[davesmith00000]

The work around is to findByTag before the updating, and calculate the delta as needed.