Fixes malf AI lockdown affecting doors on z levels other than station and mining.

Replaces a lot of z level numbers in code by their respective defines.
Adding a define for the Mining asteroid z level.

code/modules/admin/admin.dm

@@ -666,7 +666,7 @@ var/global/floorIsLava = 0
 /datum/admins/proc/unprison(var/mob/M in mob_list)
 	set category = "Admin"
 	set name = "Unprison"
-	if (M.z == 2)
+	if (M.z == ZLEVEL_CENTCOM)
 		M.loc = pick(latejoin)
 		message_admins("[key_name_admin(usr)] has unprisoned [key_name_admin(M)]")
 		log_admin("[key_name(usr)] has unprisoned [key_name(M)]")

code/modules/admin/topic.dm

@@ -1807,7 +1807,7 @@
 				message_admins("[key_name_admin(usr)] made the floor LAVA! It'll last [length] seconds and it will deal [damage] damage to everyone.")
 
 				for(var/turf/simulated/floor/F in world)
-					if(F.z == 1)
+					if(F.z == ZLEVEL_STATION)
 						F.name = "lava"
 						F.desc = "The floor is LAVA!"
 						F.overlays += "lava"
@@ -1832,7 +1832,7 @@
 						sleep(10)
 
 					for(var/turf/simulated/floor/F in world) // Reset everything.
-						if(F.z == 1)
+						if(F.z == ZLEVEL_STATION)
 							F.name = initial(F.name)
 							F.desc = initial(F.desc)
 							F.overlays.Cut()
@@ -1864,7 +1864,7 @@
 				feedback_inc("admin_secrets_fun_used",1)
 				feedback_add_details("admin_secrets_fun_used","EgL")
 				for(var/obj/machinery/door/airlock/W in world)
-					if(W.z == 1 && !istype(get_area(W), /area/bridge) && !istype(get_area(W), /area/crew_quarters) && !istype(get_area(W), /area/security/prison))
+					if(W.z == ZLEVEL_STATION && !istype(get_area(W), /area/bridge) && !istype(get_area(W), /area/crew_quarters) && !istype(get_area(W), /area/security/prison))
 						W.req_access = list()
 				message_admins("[key_name_admin(usr)] activated Egalitarian Station mode")
 				priority_announce("Centcom airlock control override activated. Please take this time to get acquainted with your coworkers.", null, 'sound/AI/commandreport.ogg')