Dropping/picking up an item shouldn't change RefNum unless the item is stacked
Currently dropping or picking up an item without an attached mwscript simply removes the item and creates a new one with the same RefId but different RefNum.
It significantly limits scripting possibilities. For example we can not check "is this dropped item the one that was stolen a minute ago, or just a similar one?".
We need to preserve RefNum unless the item is stacked.
Partially resolved by !2995 (merged), but dropping an item via GUI still creates a copy.
Edited by Petr Mikheev