Fixes #5654 by removing false damage states which caused invisible walls

Removes final set of 16 sequences for all walls as it appears that these
are not actually supposed to be used as damage states for the actual
wall, but as end pieces for each wall.  One of the pieces in particular
caused a single wall to be seen as invisible.  Fixes #5654
add FrozenActorLayer to Tiberian Sun
add blossom trees to Tiberian Sun
categorize shellmaps
fix Unit sietch does not have a sequence named bib2x
pause active animations
Merge pull request #5849 from Mailaender/active-animation-pause

Fixed active animations playing during paused games
Merge pull request #5848 from Mailaender/shellmap-category

Categorized shellmaps
Merge pull request #5847 from Mailaender/sietch-bib

Fixed the sietch crashing the game when placed on a map
Merge pull request #5844 from Mailaender/ts-blossom-trees

Added Blossom Trees to Tiberian Sun
Add beacon to parabombs, and quantise facings.
Remove obsolete BeaconDuration definitions.
Remove the obsolete flare definition from AirstrikePower.
Use AirstrikePower for spy planes.
Add a spy plane beacon, and quantise facings.
fix a NullReferenceException in preview.Map
Fixed ref and palace footprints.
Merge pull request #5856 from MustaphaTR/d2k-footprints

D2k Some Footprint Fixes
Merge pull request #5854 from pchote/ra-poster

Add beacons to the RA spy plane and parabombs
Use a shared url for news updates. Fixes #5603.