Platformer: Y-coordinate should be above first brick

[SimonN]

Lix 0.10.16

1. Assign a platformer to a walker on even ground.
2. Advance a few physics updates, until the brick physically exists as a yellow rectangle on top of the ground.
3. Optionally, advance a few more physics updates, but at most until the sprite at the bottom of this post.
4. Assign basher to the platformer.
5. Observe how the basher clears the brick because the basher is still on the ground level (from step 1).

Expected instead: The basher doesn't clear the brick. The platformer should immediately warp on top of its brick, regardless of (if and how many) physics updates we stepped forward in step 3. The platformer's feet should never be buried inside its own terrain.

(To warp the platformer onto its brick as early as possible) will align platformer physics with builder physics in this regard (of never having its feed buried inside its own terrain).

If you assign jumper to the platformer while the platformer's feet are buried in its own brick, the jumper will immediately stop and stand on the brick. This is odd. We want the jumper to jump through the air.