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
Write trait requirements in documentation.
IonCannonPower can now define how many ticks into animation the weapon impact happens (as opposed to at the end of the animation).
Bridge can now define DemolishWeapon. Defaults to previous "Demolish".
#6030 Regression fix. CreateEffectWarhead effect location and water impact sound.
Merge pull request #6158 from Phrohdoh/DocPrintRequires

Write trait requirements in documentation.
Merge pull request #6156 from UberWaffe/MinorFixes

Closes #6128
Merge pull request #6169 from UberWaffe/CWRegressFix

#6030 Regression fix: CreateEffectWarhead
New Explosion system code changes.
New explosion system yaml changes.
enum SubCell => int & Dictionary<SubCell, WVec> => WVec[]
Moved MobileInfo.SubCellOffsets to Map (dropping static) & added Map.SubCellsDefaultIndex
Load subcells and default subcell index from mod.yaml
Remove sub-cell offset bounds checking