Automatic merge of T1.6-rc2-41-gacd714487 and 9 pull requests

- Pull request #1086 at e10390b: Add Settings Exporter tool (copy settings to INI, etc)
- Pull request #1091 at 35f0051: Automatic speed control
- Pull request #1107 at f5eb3dc: Fix DPMode when last remote is moved to front.
- Pull request #1108 at 343c792: Fix Horn, Bell, and MU light conditions on AI trains
- Pull request #1109 at 0190043: Fix Erroneous Detection of Departure Before Passenger Boarding Completed
- Pull request #1110 at 387388e: Fix Activity Runner persists after loading exception
- Pull request #1082 at 5845a1a: Allow variable water level in glass gauge
- Pull request #1104 at dc2a907: Handle simple adhesion within the axle module
- Pull request #1081 at 689494b: Brake cuts power unification

Author: openrails-bot

Source/RunActivity/Viewer3D/Lights.cs

@@ -347,7 +347,7 @@ bool UpdateState()
             bool newLeftDoorOpen = !Car.Lights.IgnoredConditions[11] && Car.Train?.DoorState(DoorSide.Left) != DoorState.Closed;
             bool newRightDoorOpen = !Car.Lights.IgnoredConditions[11] && Car.Train?.DoorState(DoorSide.Right) != DoorState.Closed;
             // AI trains don't have a lead locomotive, but the upcoming lighting calculations want a lead locomotive, try to determine a lead locomotive to use
-            if (leadLocomotive == null)
+            if (leadLocomotive == null && Car.Train != null)
             {
                 // If first car is flipped, the 'lead' vehicle is actually at the rear
                 if (Car.Train.FirstCar.Flipped && Car.Train.LastCar is MSTSLocomotive)