Automatic merge of T1.6-145-g7915033ac and 11 pull requests

- Pull request #1082 at 8538170: Allow variable water level in glass gauge
- Pull request #1156 at f46d5f2: Fix incorrectly disabled options in train operations window
- Pull request #570 at 1b6b22e: glTF 2.0 support with PBR lighting
- Pull request #1091 at 492795a: Automatic speed control
- Pull request #1122 at 73c47b4: Wagon Size and Centering Controls
- Pull request #1124 at e241a0d: Built-in PBL2 brake controller
- Pull request #1157 at 39cd994: Dynamic brake authorization by TCS
- Pull request #1167 at 115325f: Fix: RunActivity slow to terminate because of long sleep in Host Process
- Pull request #1168 at 6e2942f: Fix exception when exiting with MapForm or SoundDebugForm open.
- Pull request #1169 at a984e3f: Better Handling of Wagons with Invalid Bogie Configuration
- Pull request #1171 at 8fd2066: no internet connection is available, not possible to open the Menu Content Form

Author: openrails-bot

Source/Orts.Simulation/Simulation/RollingStocks/TrainCar.cs

@@ -3039,7 +3039,7 @@ public void ComputePosition(Traveller traveler, bool backToFront, float elapsedT
                 if (p.SumWgt > 1.5f)
                     p0.AddPartLocation(1, p);
             }
-            if (Parts.Count == 2)
+            if (Parts.Count == 2 && p0.SumWgt < 1.5f)
             {
                 // Train car lacks sufficient parts to locate using linear regression
                 p0.Dir = Parts[1].Dir;
@@ -3856,7 +3856,10 @@ public void FindCenterLine()
             else // Improperly defined wagon, fallback to basic calculation
             {
                 for (int i = 0; i < 3; i++)
+                {
                     Pos[i] = (float)(SumPos[i] / SumWgt);
+                    Dir[i] = 0;
+                }
             }
 
             Roll = SumRoll / (float)SumWgt;