For 2D:
Raycast CCD now works the same as in 3D, it changes the body's velocity
to place it at the impact position instead of generating a contact point
that causes a wrong push back.
For both 2D and 3D:
The raycast CCD process reads and modifies body velocities, so it needs
to be moved to pre_solve() instead of setup() to be processed linearly
on the main thread, otherwise multithreading can cause some CCD results
to be randomly lost when multiple collisions occur.
30a608b7b9