Initial Commit for -tg- Mining

I can guarantee this will not compile, very much a WIP and currently
consists of mostly copy+pasting -tg-'s modules/mining folder over ours,
and unticking a few of our own files.

code/game/objects/items.dm

@@ -65,6 +65,12 @@
 		src:my_atom = null*/
 	return ..()
 
+/obj/item/proc/check_allowed_items(atom/target, not_inside, target_self)
+	if(((src in target) && !target_self) || ((!istype(target.loc, /turf)) && (!istype(target, /turf)) && (not_inside)) || is_type_in_list(target, can_be_placed_into))
+		return 0
+	else
+		return 1
+
 /obj/item/device
 	icon = 'icons/obj/device.dmi'