First pass at a qdel() garbage collection system for tgstation

Works pretty well. If it can't GC something, it'll just del() it and be done.
Speed is amazing, holy shit.

New procs you should be aware of:
qdel(atom/movable) - sets up an object for garbage collection. Call this rather than del(atom/movable).
atom/movable/Destroy() - called right before the object is GC'd, so it still has a loc. Also called if the object is del()'d.
new controller - garbage.dm has all the details on this. Basically it nulls all references on GC'd objects and force del() them if necessary.
Generally speaking, objects should use Destroy() for behavior prior to deletion rather than Del(). You should also always call the parent so the object gets the right gc_destroyed var set.

ISSUES:
Tries to GC mobs atm. This actually works for new players, not so much for humans/monkies/simple_animals/anything. I'm guessing it needs to clear out their mind and HUD and maybe other things.
Gibbing is really bugged. It works, but the overlays just sit there for awhile and ugh. I'm very tempted just to del() mob/living and mob/camera and call it a day.
qdel() equipment doesn't unequip the item.
Pipes don't generally GC correctly. Debugging suggests they get referenced in many pipenets and that isn't cleared properly. However some do work fine. Need assistance here.
Bots don't GC, probably in the radio controller.
Lots of other shit doesn't GC but it's hard to find them because of the pipe spam.
I think I'm calling Destroy() twice by accident.
Added a cap of 10 force del() per tick. Should maybe make this higher.

Also accidentally left testing mode on, woopsies.
Make GC'd objects super invisible to help unreference them more.
qdel() and clear contents of things when they themselves are qdel()
Forgot to add the gc_cost to the total cost of the MC.
Make items equipped by mobs unequip themselves as part of Destroy()
Change the GC's loops to for() loops instead of while() loops. Also fixed a really stupid mistake where it would cut random shit out of the destroyed list instead of what was just processed.
Made it use world.time instead of world.timeofday to get rid of stupid midnight rollover errors.
Also there's a split between caps on var clearing and deletion checks
Moved the invisibility = 101 bit out of the GC and into atom/Destroy()
WOOPS TYPO
Fixed the nuke disk qdel() fucking up
Made the singulo spawn correctly
Really minor fix for things that are qdel()'d at 0 time, which should be nothing if everything is going right.
Made gibbing not look stupid.
Also some basic stuff in an attempt to get complex mobs to GC. Still doesn't work atm.
Tweak that useless loop test. It doesn't tell me anything :(
Rename equip_to_slot_or_qdel() -> del()
Still qdel()'s them, just naming the proc back.
Should hopefully reduce the number of lines different in the pr.
Merge branch 'master' of https://github.com/tgstation/-tg-station into qdel

Hopefully nothing went wrong but you never know.

Conflicts:
	code/FEA/FEA_fire.dm
	code/controllers/supply_shuttle.dm
	code/game/gamemodes/changeling/changeling_powers.dm
	code/game/machinery/autolathe.dm
	code/game/machinery/drying_rack.dm
	code/modules/hydroponics/hydroponics.dm
	code/modules/projectiles/projectile/magic.dm
	code/modules/reagents/Chemistry-Recipes.dm
	code/modules/reagents/reagent_dispenser.dm
Fix a use_power() runtime if the object was in nullspace (was qdel()'d)
Also remove some debug shit in atmospherics I left around.
Remove a debug qdel() command.
Made atmos_alert computers GC (hopefully) and not runtime (known).
Made the singulo only qdel things once. Woops.
This was causing some runtimes and doubled reporting "Emitter deleted at (0,0,0)" etc.
Replaced a few more Del() and del() calls
Removed cigarette related reagent deleting. It's already done in atom/Destroy()!
Somehow the box away code file got unticked.
Merge branch 'master' of https://github.com/tgstation/-tg-station into qdel_r

Conflicts:
	code/game/machinery/bots/ed209bot.dm
	code/game/machinery/rechargestation.dm
	code/game/machinery/turrets.dm
	code/game/objects/structures/crates_lockers/closets.dm
	code/modules/research/circuitprinter.dm
Stat number of dels per tick
More del(AM) -> qdel(AM)
Added a new gravity generator which will produce gravity for the station.
Sprites by Ausop, which he posted in his sprite thread.

The gravity generator is very sturdy, as it is almost indestructible, but explosions can break it and it will need repairs.
Changed C4 to stop del()'ing and instead will only use ex_act().
Added an interact_offline variable for machines that will allow you to interact with them even if they are depowered. The gravity generator only uses this at the moment.

Removed the stun that people get when gravity changes.
Shuttles have gravity still.

Added a gravity generator room to the west of Engineering. It is very secure, with a foyer and requiring CE or Captain access. There are instructions on the table for repairing and enabling/disabling the machine.
* Gave the supply area gravity.
* Removed a misplaced object on the map.
Typo fixes. I'm keeping the comma-less but.