Fix server freeze on client absence.
Add WithRangeCircle trait for drawing arbitrary ranges.
Add proximity trigger plumbing.
Add UpgradeActorsNear trait for passive upgrades.
Add the stealth generator to TS.
Extend INotifyOtherProduction to all actors.
Apply upgrades to units produced within range immediately.
Add Mods.Common reference to Mods.Cnc
Move Smoke effect, ContrailFader effect, SmudgeLayer and LeaveSmudgeWarhead to Mods.Common
Move PlayMusicOnMapLoad to Mods.Common
Move ResourceClaim and ResourceClaimLayer to Mods.Common
Bring Mods.Common includes in alphabetical order
Fix spy tooltip definition.  Fixes #6665.
Fix TS offsets, selection bounds, weapon factory exits
Revert "build with latest Mono from @Xamarin"

This reverts commit f1bfbf933bb9cc170926233294f9ef9704cd3e7e.
Merge pull request #6672 from pchote/revert-mono

Revert "build with latest Mono from @Xamarin"
Merge pull request #6666 from pchote/fix-spy-tooltip

Fix spy tooltip definition.
add missing HarvesterAttackNotifier

closes #6671
document HarvesterAttack- and BaseAttackNotifier
Merge pull request #6644 from pchote/proximity-triggers

Closes #2175