Clean up check for item being equipped

Moved some common code to item.dm. Someone should probably take a look
at get_equipped_items() in inventory.dm sometime in the future.

code/game/objects/items.dm

@@ -237,6 +237,18 @@
 /obj/item/proc/equipped(var/mob/user, var/slot)
 	return
 
+//returns 1 if the item is equipped by a mob, 0 otherwise.
+//This might need some error trapping, not sure if get_equipped_items() is safe for non-human mobs.
+/obj/item/proc/is_equipped()
+	if(!ismob(loc)) 
+		return 0
+	
+	var/mob/M = loc
+	if(src in M.get_equipped_items())
+		return 1
+	else
+		return 0
+
 //the mob M is attempting to equip this item into the slot passed through as 'slot'. Return 1 if it can do this and 0 if it can't.
 //If you are making custom procs but would like to retain partial or complete functionality of this one, include a 'return ..()' to where you want this to happen.
 //Set disable_warning to 1 if you wish it to not give you outputs.

code/game/objects/items/weapons/storage/belt.dm

@@ -10,12 +10,7 @@
 
 
 /obj/item/weapon/storage/belt/proc/can_use()
-	if(!ismob(loc)) return 0
-	var/mob/M = loc
-	if(src in M.get_equipped_items())
-		return 1
-	else
-		return 0
+	return is_equipped()
 
 
 /obj/item/weapon/storage/belt/MouseDrop(obj/over_object as obj, src_location, over_location)

code/modules/clothing/spacesuits/alien.dm

@@ -198,17 +198,6 @@
 	species_restricted = list("Vox")
 	action_button_name = "Toggle the magclaws"
 
-//make sure these can only be used when equipped.
-/obj/item/clothing/shoes/magboots/vox/proc/can_use()
-	if(!ismob(loc)) 
-		return 0
-	
-	var/mob/M = loc
-	if(src in M.get_equipped_items())
-		return 1
-	else
-		return 0
-
 /obj/item/clothing/shoes/magboots/vox/attack_self(mob/user)
 	if(src.magpulse)
 		flags &= ~NOSLIP
@@ -216,7 +205,8 @@
 		canremove = 1
 		user << "You relax your deathgrip on the flooring."
 	else
-		if (!can_use())
+		//make sure these can only be used when equipped.
+		if (!is_equipped())
 			user << "You will have to put on the [src] before you can do that."
 			return
 		
@@ -228,6 +218,7 @@
 
 //In case they somehow come off while enabled.
 /obj/item/clothing/shoes/magboots/vox/dropped(mob/user as mob)
+	..()
 	if(src.magpulse)
 		user.visible_message("The [src] go limp as they are removed from [usr]'s feet.", "The [src] go limp as they are removed from your feet.")
 		flags &= ~NOSLIP