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/modules/integrated_electronics/_defines.dm

@@ -6,7 +6,7 @@
 	desc = "It's a tiny chip!  This one doesn't seem to do much, however."
 	icon = 'icons/obj/electronic_assemblies.dmi'
 	icon_state = "template"
-	w_class = 1
+	w_class = ITEMSIZE_TINY
 	var/extended_desc = null
 	var/list/inputs = list()
 	var/list/outputs = list()

code/modules/integrated_electronics/assemblies.dm

@@ -1,7 +1,7 @@
 /obj/item/device/electronic_assembly
 	name = "electronic assembly"
 	desc = "It's a case, for building electronics with."
-	w_class = 2
+	w_class = ITEMSIZE_SMALL
 	icon = 'icons/obj/electronic_assemblies.dmi'
 	icon_state = "setup_small"
 	var/max_components = 10
@@ -11,21 +11,21 @@
 /obj/item/device/electronic_assembly/medium
 	name = "electronic mechanism"
 	icon_state = "setup_medium"
-	w_class = 3
+	w_class = ITEMSIZE_NORMAL
 	max_components = 20
 	max_complexity = 80
 
 /obj/item/device/electronic_assembly/large
 	name = "electronic machine"
 	icon_state = "setup_large"
-	w_class = 4
+	w_class = ITEMSIZE_LARGE
 	max_components = 30
 	max_complexity = 120
 
 /obj/item/device/electronic_assembly/drone
 	name = "electronic drone"
 	icon_state = "setup_drone"
-	w_class = 3
+	w_class = ITEMSIZE_NORMAL
 	max_components = 25
 	max_complexity = 100
 

code/modules/integrated_electronics/tools.dm

@@ -12,7 +12,7 @@
 	icon = 'icons/obj/electronic_assemblies.dmi'
 	icon_state = "wirer-wire"
 	flags = CONDUCT
-	w_class = 2
+	w_class = ITEMSIZE_SMALL
 	var/datum/integrated_io/selected_io = null
 	var/mode = WIRE
 
@@ -111,7 +111,7 @@
 	icon = 'icons/obj/electronic_assemblies.dmi'
 	icon_state = "debugger"
 	flags = CONDUCT
-	w_class = 2
+	w_class = ITEMSIZE_SMALL
 	var/data_to_write = null
 	var/accepting_refs = 0
 
@@ -162,10 +162,10 @@
 	desc = "This kit's essential for any circuitry projects."
 	icon = 'icons/obj/electronic_assemblies.dmi'
 	icon_state = "circuit_kit"
-	w_class = 3
+	w_class = ITEMSIZE_NORMAL
 	storage_slots = 200
-	max_storage_space = 400
-	max_w_class = 3
+	max_storage_space = ITEMSIZE_COST_NORMAL * 100
+	max_w_class = ITEMSIZE_NORMAL
 	display_contents_with_number = 1
 	can_hold = list(/obj/item/integrated_circuit, /obj/item/device/integrated_electronics, /obj/item/device/electronic_assembly,
 	/obj/item/weapon/screwdriver, /obj/item/weapon/crowbar)