Added a garbage collector implementation based on rumors from Goon and proc references in released gooncode.

And holy shit it's fast

Conflicts:
	baystation12.dme
	code/ATMOSPHERICS/pipes.dm
	code/game/machinery/Sleeper.dm
	code/game/machinery/rechargestation.dm
	code/game/objects/structures/crates_lockers/crates.dm
	code/game/objects/structures/tables_racks.dm
	code/modules/mining/mine_turfs.dm
	code/modules/paperwork/photocopier.dm
	code/modules/power/cable.dm
	html/changelog.html
Forbid (un)setting step_x/y during GC.
Clean up the switch statement.
Hopefully fix more step smoothing?
I give up.
Should fix the issue of the GC turning gliding movement off
Get rid of debugging.