Fixed file paths so they work when it becomes an executable

- Changed file paths for the FXML files

src/main/java/seng302/App.java

@@ -39,7 +39,7 @@ public class App extends Application {
         //load the first container
         try {
             FXMLLoader loader = new FXMLLoader();
-            InputStream in = getClass().getClassLoader().getResourceAsStream("scenes//mainpane.fxml");
+            InputStream in = getClass().getClassLoader().getResourceAsStream("scenes/mainpane.fxml");
             mainContainer = (BorderPane) loader.load(in);
             mainScene = new Scene(mainContainer, 1200, 800);
             primaryStage.setScene(mainScene);
@@ -63,7 +63,7 @@ public class App extends Application {
      */
     public void loadPane(String fxmlName) throws Exception {
         FXMLLoader loader = new FXMLLoader();
-        InputStream in = getClass().getClassLoader().getResourceAsStream("scenes//" + fxmlName);
+        InputStream in = getClass().getClassLoader().getResourceAsStream("scenes/" + fxmlName);
         Parent page;
         try {
             page = (Parent) loader.load(in);