Centralizes weight class definitions

A lot of new defines are now in inventory_sizes.dm, which contains;
All the size identifiers (the thing that tells the game if something is bulky, or w/e).
Storage costs for all the sizes, which are exponents of two, as previously.
A few constants for inventory size.

Also changes all storage item's capacity definitions by basing it off of how many 'normal slots' exist for it.  This allows one to change the definition for all of the defines in the file, and everything will follow along without needing to change 500 files.  In testing, I made all ITEMSIZE_COST_* defines doubled, and nothing had broke.

The benefit of doing all of this is that it makes adding new weight classes in the future much simpler, and makes knowing how much space a container has easier, as seeing ITEMSIZE_COST_NORMAL * 7 means it can hold seven normal items.

code/game/objects/structures/bedsheet_bin.dm

@@ -14,7 +14,7 @@ LINEN BINS
 	throwforce = 1
 	throw_speed = 1
 	throw_range = 2
-	w_class = 2.0
+	w_class = ITEMSIZE_SMALL
 
 /obj/item/weapon/bedsheet/attack_self(mob/user as mob)
 	user.drop_item()

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

@@ -4,7 +4,7 @@
 	icon = 'icons/obj/closet.dmi'
 	icon_state = "closed"
 	density = 1
-	w_class = 5
+	w_class = ITEMSIZE_HUGE
 	var/icon_closed = "closed"
 	var/icon_opened = "open"
 	var/opened = 0

code/game/objects/structures/door_assembly.dm

@@ -4,7 +4,7 @@
 	icon_state = "door_as_0"
 	anchored = 0
 	density = 1
-	w_class = 5
+	w_class = ITEMSIZE_HUGE
 	var/state = 0
 	var/base_icon_state = ""
 	var/base_name = "airlock"

code/game/objects/structures/girders.dm

@@ -3,7 +3,7 @@
 	anchored = 1
 	density = 1
 	layer = 2
-	w_class = 5
+	w_class = ITEMSIZE_HUGE
 	var/state = 0
 	var/health = 200
 	var/cover = 50 //how much cover the girder provides against projectiles.

code/game/objects/structures/inflatable.dm

@@ -3,7 +3,7 @@
 	desc = "A folded membrane which rapidly expands into a large cubical shape on activation."
 	icon = 'icons/obj/inflatable.dmi'
 	icon_state = "folded_wall"
-	w_class = 3
+	w_class = ITEMSIZE_NORMAL
 
 	attack_self(mob/user)
 		playsound(loc, 'sound/items/zip.ogg', 75, 1)
@@ -248,8 +248,8 @@
 	desc = "Contains inflatable walls and doors."
 	icon_state = "inf_box"
 	item_state = "syringe_kit"
-	w_class = 3
-	max_storage_space = 28
+	w_class = ITEMSIZE_NORMAL
+	max_storage_space = ITEMSIZE_COST_NORMAL * 7
 	can_hold = list(/obj/item/inflatable)
 
 	New()

code/game/objects/structures/janicart.dm

@@ -291,4 +291,4 @@
 	desc = "A keyring with a small steel key, and a pink fob reading \"Pussy Wagon\"."
 	icon = 'icons/obj/vehicles.dmi'
 	icon_state = "keys"
-	w_class = 1
+	w_class = ITEMSIZE_TINY

code/game/objects/structures/lattice.dm

@@ -5,7 +5,7 @@
 	icon_state = "latticefull"
 	density = 0
 	anchored = 1.0
-	w_class = 3
+	w_class = ITEMSIZE_NORMAL
 	layer = 2.3 //under pipes
 	//	flags = CONDUCT
 

code/game/objects/structures/mop_bucket.dm

@@ -4,7 +4,7 @@
 	icon = 'icons/obj/janitor.dmi'
 	icon_state = "mopbucket"
 	density = 1
-	w_class = 3
+	w_class = ITEMSIZE_NORMAL
 	pressure_resistance = 5
 	flags = OPENCONTAINER
 	var/amount_per_transfer_from_this = 5	//shit I dunno, adding this so syringes stop runtime erroring. --NeoFite

code/game/objects/structures/signs.dm

@@ -4,7 +4,7 @@
 	opacity = 0
 	density = 0
 	layer = 3.5
-	w_class = 3
+	w_class = ITEMSIZE_NORMAL
 
 /obj/structure/sign/ex_act(severity)
 	switch(severity)
@@ -37,7 +37,7 @@
 	name = "sign"
 	desc = ""
 	icon = 'icons/obj/decals.dmi'
-	w_class = 3		//big
+	w_class = ITEMSIZE_NORMAL		//big
 	var/sign_state = ""
 
 /obj/item/sign/attackby(obj/item/tool as obj, mob/user as mob)	//construction

code/game/objects/structures/stool_bed_chair_nest/bed.dm

@@ -226,7 +226,7 @@
 	desc = "A collapsed roller bed that can be carried around."
 	icon = 'icons/obj/rollerbed.dmi'
 	icon_state = "folded"
-	w_class = 4.0 // Can't be put in backpacks. Oh well.
+	w_class = ITEMSIZE_LARGE // Can't be put in backpacks. Oh well.
 
 /obj/item/roller/attack_self(mob/user)
 		var/obj/structure/bed/roller/R = new /obj/structure/bed/roller(user.loc)

code/game/objects/structures/stool_bed_chair_nest/stools.dm

@@ -8,7 +8,7 @@ var/global/list/stool_cache = list() //haha stool
 	icon_state = "stool_preview" //set for the map
 	force = 10
 	throwforce = 10
-	w_class = 5
+	w_class = ITEMSIZE_HUGE
 	var/base_icon = "stool_base"
 	var/material/material
 	var/material/padding_material

code/game/objects/structures/tank_dispenser.dm

@@ -5,7 +5,7 @@
 	icon_state = "dispenser"
 	density = 1
 	anchored = 1.0
-	w_class = 5
+	w_class = ITEMSIZE_HUGE
 	var/oxygentanks = 10
 	var/phorontanks = 10
 	var/list/oxytanks = list()	//sorry for the similar var names

code/game/objects/structures/target_stake.dm

@@ -5,7 +5,7 @@
 	icon = 'icons/obj/objects.dmi'
 	icon_state = "target_stake"
 	density = 1
-	w_class = 5
+	w_class = ITEMSIZE_HUGE
 	flags = CONDUCT
 	var/obj/item/target/pinned_target // the current pinned target
 

code/game/objects/structures/windoor_assembly.dm

@@ -16,7 +16,7 @@ obj/structure/windoor_assembly
 	anchored = 0
 	density = 0
 	dir = NORTH
-	w_class = 3
+	w_class = ITEMSIZE_NORMAL
 
 	var/obj/item/weapon/airlock_electronics/electronics = null
 	var/created_name = null

code/game/objects/structures/window.dm

@@ -3,7 +3,7 @@
 	desc = "A window."
 	icon = 'icons/obj/structures.dmi'
 	density = 1
-	w_class = 3
+	w_class = ITEMSIZE_NORMAL
 
 	layer = 3.2//Just above doors
 	pressure_resistance = 4*ONE_ATMOSPHERE