[ODE] Geometry passing through / timestep size

[Adam Moravanszky]

>       Move the body back to the earliest collision point.


This will only work perfectly if you somehow make sure that you no other
body already moved to the position where your current body started,
otherwise you will move it back into a (nonexistant) collision.  The easiest
thing to do is to move back all the bodies where they started, but that's a
pain.  Better is to just check if your original position is still
available... if its not, then you have a problem.  Fortunately really fast
moving objects rarely do so in clusters.

--
-- Adam