Implements Destroy() for organs

- This fixes annoying roundstart GC errors, and should fix other limb/organ related GC errors as well.

code/modules/organs/organ.dm

@@ -24,6 +24,27 @@ var/list/organ_cache = list()
 									  // links chemical IDs to number of ticks for which they'll stay in the blood
 	germ_level = 0
 
+/obj/item/organ/Destroy()
+	if(!owner)
+		return ..()
+
+	if((owner.internal_organs) && (src in owner.internal_organs))
+		owner.internal_organs -= src
+
+	if((owner.internal_organs_by_name) && (src in owner.internal_organs_by_name))
+		owner.internal_organs_by_name -= src
+
+	if((owner.organs) && (src in owner.organs))
+		owner.internal_organs -= src
+
+	if((owner.organs_by_name) && (src in owner.organs_by_name))
+		owner.organs_by_name -= src
+
+	if(src in owner.contents)
+		owner.contents -= src
+
+	return ..()
+
 /obj/item/organ/proc/update_health()
 	return
 

code/modules/organs/organ_external.dm

@@ -48,6 +48,20 @@
 	var/can_grasp
 	var/can_stand
 
+/obj/item/organ/external/Destroy()
+	if(parent && parent.children)
+		parent.children -= src
+
+	if(children)
+		for(var/obj/item/organ/external/C in children)
+			qdel(C)
+
+	if(internal_organs)
+		for(var/obj/item/organ/O in internal_organs)
+			qdel(O)
+
+	return ..()
+
 /obj/item/organ/external/attack_self(var/mob/user)
 	if(!contents.len)
 		return ..()