Merge pull request #9515 from Ghommie/Ghommie-cit241

Porting "Moves machine/computer frames and structures below object layer." and lowering trays layer.

code/game/objects/structures/crates_lockers/closets.dm

@@ -4,7 +4,6 @@
 	icon = 'icons/obj/closet.dmi'
 	icon_state = "generic"
 	density = TRUE
-	layer = BELOW_OBJ_LAYER
 	var/icon_door = null
 	var/icon_door_override = FALSE //override to have open overlay use icon different to its base's
 	var/secure = FALSE //secure locker or not, also used if overriding a non-secure locker with a secure door overlay to add fancy lights

code/game/objects/structures/girders.dm

@@ -4,7 +4,6 @@
 	desc = "A large structural assembly made out of metal; It requires a layer of metal before it can be considered a wall."
 	anchored = TRUE
 	density = TRUE
-	layer = BELOW_OBJ_LAYER
 	var/state = GIRDER_NORMAL
 	var/girderpasschance = 20 // percentage chance that a projectile passes through the girder.
 	var/can_displace = TRUE //If the girder can be moved around by wrenching it

code/game/objects/structures/mineral_doors.dm

@@ -6,6 +6,7 @@
 	density = TRUE
 	anchored = TRUE
 	opacity = TRUE
+	layer = CLOSED_DOOR_LAYER
 
 	icon = 'icons/obj/doors/mineral_doors.dmi'
 	icon_state = "metal"
@@ -90,6 +91,7 @@
 	flick("[initial_state]opening",src)
 	sleep(10)
 	density = FALSE
+	layer = OPEN_DOOR_LAYER
 	state = 1
 	air_update_turf(1)
 	update_icon()
@@ -111,6 +113,7 @@
 	density = TRUE
 	set_opacity(TRUE)
 	state = 0
+	layer = initial(layer)
 	air_update_turf(1)
 	update_icon()
 	isSwitchingStates = 0

code/game/objects/structures/morgue.dm

@@ -307,7 +307,7 @@ GLOBAL_LIST_EMPTY(crematoriums)
 /obj/structure/tray
 	icon = 'icons/obj/stationobjs.dmi'
 	density = TRUE
-	layer = BELOW_OBJ_LAYER
+	layer = TRAY_LAYER
 	var/obj/structure/bodycontainer/connected = null
 	anchored = TRUE
 	pass_flags = LETPASSTHROW

code/game/objects/structures/reflector.dm

@@ -5,7 +5,6 @@
 	desc = "A base for reflector assemblies."
 	anchored = FALSE
 	density = FALSE
-	layer = BELOW_OBJ_LAYER
 	var/deflector_icon_state
 	var/image/deflector_overlay
 	var/finished = FALSE

code/game/objects/structures/transit_tubes/transit_tube_pod.dm

@@ -4,7 +4,6 @@
 	animate_movement = FORWARD_STEPS
 	anchored = TRUE
 	density = TRUE
-	layer = BELOW_OBJ_LAYER
 	var/moving = 0
 	var/datum/gas_mixture/air_contents = new()