Fix Floating Wrecks

The layer settings for pos[2] are reverted to what they were in steam. @Crotalus - Any particular reason for changing these in the first place, or was it PilOt?

The bug was caused by TryCopyPose which for some reason doesn't play nice with Air units killed by the map. I limited it to non-Air, as it does seem to work really nicely with land units to make all the wreckages different.