Fix BibLayer style nits.
Add FrozenUnderFog property to BibLayer.

Note: This implements the desired behavior
for FrozenUnderFog, so is still inconsistent
with its current (broken) behavior.
Fix SmudgeLayer style nits.
Freeze smudges under fog.
Fix ResourceLayer style nits.
Freeze resources under fog.
Use the rendered resource state for the harvest order targeter.
Hide explosions under fog.
Hide corpses under fog.
Hide smoke under fog.
Hide Repair, Powerdown icons when cloaked. Fixes #3588. Fixes #3502.
Tidy HiddenUnderFog.
Fix FrozenUnderFog.
Enable FrozenUnderFog in C&C and RA.
Hide crate effects / rank animation under fog.
Merge pull request #3596 from pchote/fog-visibility-freezing

Fog visibility freezing fixes #3206 et al