Automatic merge of T1.6-147-g31e3fe251 and 10 pull requests

- Pull request #1082 at e4d7f70: Allow variable water level in glass gauge
- 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 #1130 at 0f4342d: Fix F9 points to an incorrect car ID.
- Pull request #1157 at 39cd994: Dynamic brake authorization by TCS
- Pull request #1167 at d5c0d64: Fix: RunActivity slow to terminate because of long sleep in Host Process
- Pull request #1171 at 50efb5b: no internet connection is available, not possible to open the Menu Content Form
- Pull request #1169 at 6cf8c3e: Better Handling of Wagons with Invalid Bogie Configuration

Author: openrails-bot

Source/Menu/ContentForm.cs

@@ -90,7 +90,7 @@ public ContentForm(UserSettings settings, string baseDocumentationUrl)
             Settings.Content.ContentRouteSettings.LoadContent(ref errorMsg);
             if (!string.IsNullOrEmpty(errorMsg))
             {
-                string message = Catalog.GetStringFmt("Not connected to internet, automatic download not available. Error: {0}", errorMsg);
+                string message = Catalog.GetStringFmt("Failed to access the content repository (check Internet connection); automatic download not available. Error: {0}", errorMsg);
                 MessageBox.Show(message, Catalog.GetString("Attention"), MessageBoxButtons.OK, MessageBoxIcon.Error);
                 NoInternet = true;
             }