* Fix: Blobs respect gravity if not otherwise prevented.
Tweak: Blobs do not directly interact with stairs
Tweak: Blobs, when expanding against a stair's middle structure, can grow up Z-levels if the turf allows.
Tweak: Blobs, if controlled by a player, may grow upward or downward, if the turfs allow.
Fix: Blob Overmind is no longer affected by gravity.
* Fringe case deleted blobs are null-loc'd for GC so they are not stuck in-map.
Railing checks properly function.
* Sideports a couple of init unit tests from Neb.
* Trying to unfuck initialize logic.
* Removing del()s.
* Adjusting return values to Initialize().
* Moving some dangerous object logic from obj onto the two types that use it.
* Rolling back some init changes and commenting out initialized atom unit test.
* this comment formatting is a minor war crime
* Removed sleep() from signaler circuit Initialize().
* Additional Init fixes post-rebase.
* Uncomments subsystem test since that's passing.
* Rewrites stairs
* Stairs go up and down
* Adds animation
* Polishes movement interactions.
* Grabs are moved across stairs, adds changelog
* Removes debug logs
