Automatic merge of T1.6-rc3-30-gdf7bf1a26 and 10 pull requests

- Pull request #1104 at c039a26: Handle simple adhesion within the axle module
- Pull request #1057 at 1c2bcb4: Switchable brake system
- Pull request #1086 at e10390b: Add Settings Exporter tool (copy settings to INI, etc)
- Pull request #1091 at 2391bc0: Automatic speed control
- Pull request #1110 at 387388e: Fix Activity Runner persists after loading exception
- Pull request #1115 at 270f22f: Do not activate ETS switch if no suitable cars are attached
- Pull request #1121 at 91d2d26: Manually Override Articulation
- Pull request #1123 at dc286f5: Handle null control active locomotive
- Pull request #1082 at 5845a1a: Allow variable water level in glass gauge
- Pull request #1081 at 689494b: Brake cuts power unification

Author: openrails-bot

Source/Orts.Simulation/Common/Scripting/PowerSupply/ControlCarPowerSupply.cs

@@ -51,11 +51,11 @@ protected override void SetCurrentElectricTrainSupplyState(PowerSupplyState stat
         protected override void SetCurrentDynamicBrakeAvailability(bool avail) {}
         public void SignalEventToControlActiveLocomotive(PowerSupplyEvent evt)
         {
-            ControlActiveLocomotive.LocomotivePowerSupply.HandleEvent(evt);
+            ControlActiveLocomotive?.LocomotivePowerSupply.HandleEvent(evt);
         }
         public void SignalEventToControlActiveLocomotive(PowerSupplyEvent evt, int id)
         {
-            ControlActiveLocomotive.LocomotivePowerSupply.HandleEvent(evt, id);
+            ControlActiveLocomotive?.LocomotivePowerSupply.HandleEvent(evt, id);
         }
     }
 }