0002826: LOD inventory entities sometimes re-appear
Description
It seems that items picked up (like keys) are still existing, but simply made invisible/hidden when the pickup occurs.
If the item in question is an LOD entity, the LOD code/check can make the entity re-appear, probably because it sees it as hidden, but not as in the inventory.
Steps To Reproduce
Start test/stack.map, and pickup any of the three "Mysterious Key"s on the table. Quite alot of the time they re-appear half a second later,and can be picked up a second time.
* Add DisableLOD() and EnableLOD() on entities, and make it work
* Call DisableLOD() on entities that go into the inventory, or are shouldered, and later when they are dropped, call EnableLOD() again on them.
