for(var/bad_code in world)

Removes a very large amount of world loops.
Adds a macro to painlessly generate a global list, and the needed code to modify the list when an object is made or deleted automatically.
Cleans up some commented out code.

code/controllers/emergency_shuttle_controller.dm

@@ -84,7 +84,7 @@ var/global/datum/emergency_shuttle_controller/emergency_shuttle
 
 	evac = 1
 	emergency_shuttle_called.Announce(replacetext(using_map.emergency_shuttle_called_message, "%ETA%", "[estimated_time] minute\s"))
-	for(var/area/A in world)
+	for(var/area/A in all_areas)
 		if(istype(A, /area/hallway))
 			A.readyalert()
 
@@ -116,7 +116,7 @@ var/global/datum/emergency_shuttle_controller/emergency_shuttle
 	if (evac)
 		emergency_shuttle_recalled.Announce(using_map.emergency_shuttle_recall_message)
 
-		for(var/area/A in world)
+		for(var/area/A in all_areas)
 			if(istype(A, /area/hallway))
 				A.readyreset()
 		evac = 0

code/controllers/master_controller.dm

@@ -49,67 +49,8 @@ datum/controller/game_controller/proc/setup()
 // #endif
 
 datum/controller/game_controller/proc/setup_objects()
-	// #if !UNIT_TEST
-	// var/initialized_objects = 0
-	// #endif
-
 	// Set up antagonists.
 	populate_antag_type_list()
 
 	//Set up spawn points.
 	populate_spawn_points()
-
-/*
-	admin_notice("<span class='danger'>Initializing Floor Decals</span>", R_DEBUG)
-	var/list/turfs_with_decals = list()
-	for(var/obj/effect/floor_decal/D in world)
-		var/T = D.add_to_turf_decals()
-		if(T) turfs_with_decals |= T
-		CHECK_SLEEP_MASTER
-	for(var/item in turfs_with_decals)
-		var/turf/T = item
-		if(T.decals) T.apply_decals()
-		CHECK_SLEEP_MASTER
-	floor_decals_initialized = TRUE
-	sleep(1)
-
-	admin_notice("<span class='danger'>Initializing objects</span>", R_DEBUG)
-	for(var/atom/movable/object in world)
-		if(!QDELETED(object))
-			object.initialize()
-			CHECK_SLEEP_MASTER
-	sleep(1)
-
-	admin_notice("<span class='danger'>Initializing areas</span>", R_DEBUG)
-	for(var/area/area in all_areas)
-		area.initialize()
-		CHECK_SLEEP_MASTER
-	sleep(1)
-
-	admin_notice("<span class='danger'>Initializing atmos machinery connections.</span>", R_DEBUG)
-	for(var/obj/machinery/atmospherics/machine in machines)
-		machine.atmos_init()
-		CHECK_SLEEP_MASTER
-
-	admin_notice("<span class='danger'>Initializing pipe networks</span>", R_DEBUG)
-	for(var/obj/machinery/atmospherics/machine in machines)
-		machine.build_network()
-		CHECK_SLEEP_MASTER
-
-	admin_notice("<span class='danger'>Initializing atmos machinery.</span>", R_DEBUG)
-	for(var/obj/machinery/atmospherics/unary/U in machines)
-		if(istype(U, /obj/machinery/atmospherics/unary/vent_pump))
-			var/obj/machinery/atmospherics/unary/vent_pump/T = U
-			T.broadcast_status()
-		else if(istype(U, /obj/machinery/atmospherics/unary/vent_scrubber))
-			var/obj/machinery/atmospherics/unary/vent_scrubber/T = U
-			T.broadcast_status()
-		CHECK_SLEEP_MASTER
-
-	admin_notice("<span class='danger'>Initializing turbolifts</span>", R_DEBUG)
-	for(var/thing in turbolifts)
-		var/obj/turbolift_map_holder/lift = thing
-		if(!QDELETED(lift))
-			lift.initialize()
-			CHECK_SLEEP_MASTER
-	*/

code/controllers/subsystems/air.dm

@@ -35,7 +35,7 @@ SUBSYSTEM_DEF(air)
 
 	current_cycle = 0
 	var/simulated_turf_count = 0
-	for(var/turf/simulated/S in world)
+	for(var/turf/simulated/S in turfs)
 		simulated_turf_count++
 		S.update_air_properties()
 		CHECK_TICK

code/controllers/subsystems/atoms.dm

@@ -46,7 +46,7 @@ SUBSYSTEM_DEF(atoms)
 				CHECK_TICK
 	else
 		count = 0
-		for(var/atom/A in world)
+		for(var/atom/A in world) // This must be world, since this operation adds all the atoms to their specific lists.
 			if(!A.initialized)
 				InitAtom(A, mapload_arg)
 				++count

code/controllers/subsystems/xenoarch.dm

@@ -30,7 +30,7 @@ SUBSYSTEM_DEF(xenoarch)
 	. = ..()
 
 /datum/controller/subsystem/xenoarch/proc/SetupXenoarch()
-	for(var/turf/simulated/mineral/M in world)
+	for(var/turf/simulated/mineral/M in turfs)
 		if(!M.density)
 			continue