* Updated to ZDoom 4164:
- Properly transfer powerups between morphed and unmorphed actors by calling EndEffect() on the powerups before they transfer ownership, then calling InitEffect() on them after they transfer ownership.
- Fixed: stat skyboxes output was broken.
- Fixed: Skyboxes never cleared planes when a 3D floor was in view.

git-svn-id: http://mancubus.net/svn/hosted/gzdoom/trunk@1532 b0f79afe-0144-0410-b225-9a4edf0717df