Adds tgstation's fix air for admins (#49)

sandcode/code/modules/admin/verbs/fix_air.dm

@@ -0,0 +1,22 @@
+// Proc taken from yogstation, credit to nichlas0010 for the original
+/client/proc/fix_air(turf/open/T in world)
+	set name = "Fix Air"
+	set category = "Admin - Game"
+	set desc = "Fixes air in specified radius."
+
+	if(!holder)
+		to_chat(src, "Only administrators may use this command.", confidential = TRUE)
+		return
+
+	if(check_rights(R_ADMIN, TRUE))
+		var/range = input("Enter range:", "Num", 2) as num
+		message_admins("[key_name_admin(usr)] fixed air with range [range] at [ADMIN_VERBOSEJMP(T)]")
+		log_game("[key_name_admin(usr)] fixed air with range [range] at [AREACOORD(T)]")
+		var/datum/gas_mixture/GM = new
+		for(var/turf/open/F in range(range, T))
+			if(F.blocks_air)
+			//skip walls
+				continue
+			GM.parse_gas_string(F.initial_gas_mix)
+			F.copy_air(GM)
+			F.update_visuals()