UtBS 12: unstore_unit is capable of relocating units
UtBS 12: Spawn bats on rainforest, not tropical forest

While there was some tropical forest on the map, most has been changed
to rainforest. This change ensures that the bats stay in the jungle
proper. Also, by eliminating tropical forest as an option, the bats
will never spawn in the trees in the southern part of the island.
UtBS 12: Get rid of overridden flag variant