Updates storage costs

Storage cost of an item is now twice that of the next smallest item, instead of being equal to the w_class.
Items with w_class 1 or 2 are unaffected. This produces much better behaviour for containers that are limited
by storage space instead of slots, such as how toolboxes are planned to work in a future update.

code/modules/research/xenoarchaeology/finds/finds.dm

@@ -208,7 +208,8 @@
 			new_item.icon_state = "box"
 			var/obj/item/weapon/storage/box/new_box = new_item
 			new_box.max_w_class = pick(1,2,2,3,3,3,4,4)
-			new_box.max_combined_w_class = rand(new_box.max_w_class, new_box.max_w_class * 10)
+			var/storage_amount = 2**(new_box.max_w_class-1)
+			new_box.max_storage_space = rand(storage_amount, storage_amount * 10)
 			if(prob(30))
 				apply_image_decorations = 1
 		if(12)

code/modules/research/xenoarchaeology/tools/tools.dm

@@ -31,6 +31,6 @@
 	slot_flags = SLOT_BELT | SLOT_POCKET
 	w_class = 3
 	storage_slots = 50
-	max_combined_w_class = 200 //Doesn't matter what this is, so long as it's more or equal to storage_slots * ore.w_class
+	max_storage_space = 200 //Doesn't matter what this is, so long as it's more or equal to storage_slots * ore.w_class
 	max_w_class = 3
 	can_hold = list(/obj/item/weapon/fossil)

code/modules/research/xenoarchaeology/tools/tools_pickaxe.dm

@@ -117,8 +117,8 @@
 	/obj/item/weapon/pickaxe/four_pick,\
 	/obj/item/weapon/pickaxe/five_pick,\
 	/obj/item/weapon/pickaxe/six_pick)
-	max_combined_w_class = 17
-	max_w_class = 4
+	max_storage_space = 18
+	max_w_class = 3
 	use_to_pickup = 1 // for picking up broken bulbs, not that most people will try
 
 /obj/item/weapon/storage/box/excavation/New()