Add reverse that allow to switch interior/exterior of a labyrinth

- invert create a new labyrinth walls are path of previous.
  - grow then new labrynth is bigger, else shrink.

java/org/artisanlogiciel/games/maze/gui/Display.java

@@ -45,6 +45,7 @@ implements StatusListener
     LabyModel model;
     boolean autoSize;
     boolean statusEnable = true;
+    boolean mGrow = false;
 
     MazeParams params = null;
     JTextField statusField = null;
@@ -150,6 +151,14 @@ implements StatusListener
         solving.resolve(solving.getWidth() - 1, solving.getHeight() - 1, maze);
     }
 
+    boolean reverse(boolean grow) {
+        boolean done = model.reverse(grow);
+        if ( done ) {
+            refresh();
+        }
+        return done;
+    }
+
     void goNorth() {
         maze.goNorth();
     }
@@ -513,6 +522,18 @@ implements StatusListener
 
             resolveQuitBar.add(resolveButton);
 
+            JButton reverseButton = new JButton(labels.getString("reverse"));
+            reverseButton.addActionListener(new ActionListener() {
+                public void actionPerformed(ActionEvent evt) {
+                    //
+                    addStatus("Reversing");
+                    mGrow ^= reverse(mGrow);
+                }
+            });
+
+            resolveQuitBar.add(reverseButton);
+
+
             final JButton quitButton = new JButton(labels.getString("quit"));
             Action quitAction = new AbstractAction() {
                 public void actionPerformed(ActionEvent evt) {