Generalized w_class to obj level, defaulting to null.

code/game/objects/items.dm

@@ -1,6 +1,8 @@
 /obj/item
 	name = "item"
 	icon = 'icons/obj/items.dmi'
+	w_class = 3.0
+
 	var/image/blood_overlay = null //this saves our blood splatter overlay, which will be processed not to go over the edges of the sprite
 	var/abstract = 0
 	var/r_speed = 1.0
@@ -8,7 +10,6 @@
 	var/burn_point = null
 	var/burning = null
 	var/hitsound = null
-	var/w_class = 3.0
 	var/slot_flags = 0		//This is used to determine on which slots an item can fit.
 	var/no_attack_log = 0			//If it's an item we don't want to log attack_logs with, set this to 1
 	pass_flags = PASSTABLE

code/game/objects/objs.dm

@@ -1,7 +1,7 @@
 /obj
 	//Used to store information about the contents of the object.
 	var/list/matter
-
+	var/w_class // Size of the object.
 	var/list/origin_tech = null	//Used by R&D to determine what research bonuses it grants.
 	var/unacidable = 0 //universal "unacidabliness" var, here so you can use it in any obj.
 	animate_movement = 2
@@ -10,7 +10,6 @@
 	var/sharp = 0		// whether this object cuts
 	var/edge = 0		// whether this object is more likely to dismember
 	var/in_use = 0 // If we have a user using us, this will be set on. We will check if the user has stopped using us, and thus stop updating and LAGGING EVERYTHING!
-
 	var/damtype = "brute"
 	var/force = 0
 	var/armor_penetration = 0

code/game/objects/structures.dm

@@ -1,5 +1,6 @@
 /obj/structure
 	icon = 'icons/obj/structures.dmi'
+	w_class = 10
 
 	var/climbable
 	var/breakable