Entities that become objects in the level need to clobber each other in the editor

[city41]

Sprites can overlap all they want. But usually objects clobber each other. Have editorSlice do the clobbering to better show the user what their level will really be like.

[city41]

@OQUENDOMAN I am deleting all your disassembly links. I hate to do this, but I need to give you a warning. You are jeopardizing Smaghetti. If you continue to link to copyrighted content, I will unfortunately need to ban you from the repo.