Support additive blending for D2K explosions.
Merge pull request #3683 from pchote/fancy-explosion-support

Add engine support for D2K explosions
Merge pull request #3678 from Mailaender/d2k-early-merge

Non-controversial early merge cleanups from the native-r8s branch
load the Dune 2000 mouse curser from the native MOUSE.R8 format
load Dune 2000 walls directly from DATA.R8
moved the towers to DATA.R8 sequences
migrate all other buildings to DATA.R8 sequences

4th conyard might be for the Corrino faction
TODO: active animations are yet unused overlays
replace the infantry sequences with transposed DATA.R8 frames
load Dune 2000 aircraft directly from DATA.R8
load projectiles, muzzles and explosions from DATA.R8
move vehicles to load sprites from DATA.R8 directly
read the production icons from sequences

this allows d2k to read them from DATA.R8 without trouble
read support power icons from sequences

so that d2k can grab them from DATA.R8
port map actors to DATA.R8 sequences
load DATA.R8 per default and not mouse.shp
remove dependency on mouse.shp conversions
package the tilesets that yet require tmp conversion

closes #2345
remove all remaining DATA.R8 → SHP conversions entirely

closes #2566
remove utility dependency on d2k DLL

partly fixes #3298
remove unused allyrepair

wrong palette anyway