Place the previously unused arctic fox model on polar sea following D524.
Replace dead tree actors with actual trees.
Replace shark actor with actual sharks on Necropolis (should have been done in D511).
Remove actor fish that would still be misleading on Tuscan Acropolis (4) (the river is too small for ships).

Differential Revision: https://code.wildfiregames.com/D525
Patch By: phormio