Implement Format80 RLE compression
Fix and optimize FindTilesInCircle
Fix editor position of TD tiberium trees.
Remove duplicate split sequence.
Make blue tib tree more centered on cell (fixes #5744).

Remove obsolete splitblue art.
Merge pull request #5792 from reaperrr/tib-tree-fixes

TD Tiberium tree fixes
Merge pull request #5678 from pavlos256/find-tiles-in-circle

Fix and optimize FindTilesInCircle
Merge pull request #5781 from pavlos256/format80-write-rle

Implement Format80 RLE compression
StyleCop
document for modders
new trait Parachtuable that decides on the fate upon landing
new setting to allow unlucky paratroopers
@pchote's quest against legacy truth value definitions
merge ParachuteAttachment and Parachutable
make the parachute animation optional

instead of hard-coding default sprite sequences
make the parachute palettes configurable
add a customizable parachute shadow

closes #3335
make the fallrate customizable
fix shadow sprite not being rendered on the ground