destructible trees for both CnC and RA mod

- move DeadBuildingState to OpenRA.Mods.RA
- don't loop sequences with length > 1
Merge pull request #2612 from Mailaender/burning-trees

Destructible trees for both CnC and RA mod
simplify desktop file installation on Linux

the old Ubuntu build machine is unable to do it
Merge pull request #2757 from Mailaender/desktop-fix

Fix missing .desktop file in latest playtests
Merge pull request #2756 from chrisforbes/master

Fix desync on win or lose