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
don't display idle overlays during actor transformations

fixes #6018
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.
Merge pull request #6110 from pchote/unit-upgrades

Add an actor upgrade system (+ overhauls veterancy and crates)
Add support for mission objectives

Objectives can be either primary or secondary objectives. Primary ones
influence the outcome of the game.  If all primary objectives are
completed the game is won, and lost when any of them fails.

Objectives can be added at any stage during the game, allowing to react
dynamically to game events.

The objectives backend only contains the information about the
objectives themselves. It does not check if objectives are completed or
failed.  Instead, the state of objectives must be manually marked. The
backend, however, does check whether the game is won or lost.
Make Conquest- and StrategicVictoryConditions use objectives backend

Note: 3rd party KotH maps will need to be modified to work correctly
with this change.  Previously, StrategicVictoryConditions was a
supplement to ConquestVictoryConditions.  After this change, each works
by itself.  So KotH maps will need to remove the ConquestVictoryConditions
trait from the player definitions, or both victory conditions will have
to be satisfied to win the game.
Move trigger lists into a dictionary for easier access and enumeration
Add mission objectives to Lua interface
Make CheckboxWidget honour GetText()