Fixes gem mine desert palette.
Merge pull request #5987 from reaperrr/gem-mine-palette

Fixes gem mine desert palette
Fix frozen actors being targetable under shroud. Fixes #5979, #5978.
Merge pull request #5989 from pchote/frozen-target-fix

Fix frozen actors being targetable under shroud.
Fix scripted paradrops.
Fix old-lua paradrop too.
Merge pull request #5988 from pchote/shellmap-paradrop

Fix scripted paradrops.
Don’t cancel MoveAdjacentTo / MoveWithinRange when target becomes invalid.

Move to the last known position instead.  Fixes #5968.
Calculate a new path (and possibly new target cell) if the original path is blocked.
Fix a typo.