multi needs to clean up controls list after ship is destroyed...

When a ship is destoryed, its controls record remains in the controls list so that new ships cannot be created. What should happen is that the control is eliminated and the ship that was destroyed is returned to the free list of ships to be allocated.

Start by tracing the code that handles ship destruction in the multiplayer flow, then follow how the controls list and free ship list are maintained. Done means the destroyed ship's control entry is removed and the ship becomes available for allocation again, with the multiplayer behavior checked to confirm new ships can be created.

Written by the indexing model from the issue text.