* Now they won't try and bump you up to the next z on the "lower" step of the stairway. They also don't directly set `loc` Therefore pulling objects up/down actually works.
* Sets their layer so they won't appear above actual objects and mobs.
* Global procs should start with /proc
* Use to_chat() macro
* Added utility to find all z-levels are connected (transitively adjacent) and utility to test if two levels are connected.