Issue 66: client side error pop ups use default javaFx style

- created JFeonix style pop up to replace the default one

tags: #story[1273]

src/main/java/seng302/visualiser/controllers/ViewManager.java

@@ -28,6 +28,7 @@ import seng302.utilities.BonjourInstallChecker;
 import seng302.utilities.Sounds;
 import seng302.visualiser.GameClient;
 import seng302.visualiser.controllers.dialogs.KeyBindingDialogController;
+import seng302.visualiser.controllers.dialogs.PopupDialogController;
 
 public class ViewManager {
 
@@ -229,6 +230,26 @@ public class ViewManager {
         keyBindingDialog.close();
     }
 
+    public PopupDialogController showPopupDialog() {
+        FXMLLoader dialogContent = new FXMLLoader(
+            getClass().getResource("/views/dialogs/PopupDialog.fxml"));
+        for (Node node : decorator.getChildren()) {
+            if (node instanceof StackPane) {
+                try {
+                    JFXDialog dialog = new JFXDialog((StackPane) node, dialogContent.load(),
+                        DialogTransition.CENTER);
+                    PopupDialogController popupDialogController = dialogContent.getController();
+                    popupDialogController.setPopupDialog(dialog);
+                    dialog.show();
+                    return popupDialogController;
+                } catch (IOException e) {
+                    logger.error("Cannot load Popup dialog");
+                }
+            }
+        }
+        return null;
+    }
+
     /**
      * Show a snackbar at the bottom of the app for 1 second.
      *