only notify when the lobby settings differ from the default
announce map changes
announce kicks and bans
make the change notifications more natural
notify about difficulty level changes
disable music installation during a game

closes #6058
don't display idle overlays during actor transformations

fixes #6018
Fix observer widgets not showing up when a player loses

Fixes #6172.
Fix breakage of --upgrade-map in OpenRA.Utility

Closes #6045
Fix Apache's guns being blocked by walls in TD.

Closes #6192.
Merge pull request #6194 from obrakmann/fix6192

Fix Apache's guns being blocked by walls in TD.
Merge pull request #6150 from Mailaender/disable-music-install-during-games

Disabled music installation during matches
Merge pull request #6151 from Mailaender/disable-idle-overlay-during-transform

Fixed idle overlays being displayed during actor transformations
Merge pull request #6134 from Mailaender/lobby-notify-followup

Made the lobby notifications less spammy and added some more cases
Support production of actors without IFacing.
Introduce IUpgradable and purchasable unit upgrades.
Reimplement UnitUpgradeCrate using IUpgradable.
Reimplement unit levels using IUpgradable.
Add FriendlyFire property to GivesExperience.
Replace CloakCrateAction with upgrades.