Make FMVPlayer in TD use a completely black background

Fixes #6211.
Make FMVPlayer in RA use a completely black background
5936 Advanced Power Plant have a different layout in the original
Merge pull request #6230 from havok13888/AdvancedPowePlant

#5936 Advanced Power Plant have a different layout in the original
Merge pull request #6220 from obrakmann/fix6211

Make background of FMVPlayers in TD and RA black
avoid NullReferenceException in updatedRegion

fixes #6166
Merge pull request #6226 from Mailaender/shroud-updatedregion-nre

Fixed a crash when there are no actors to reveal shroud on the map.
Fixed UpgradeRules for #6030.
Fixed Warhead ValidTargets and InvalidTargets.
#6030 regression fix. Added EffectivenessAgainst <= 0 check to IsvalidAgainst for Warhead.
Made Effect, Resource and Smudge warheads return 0% effective against actors.
Fixed custom weapon rules in maps.