wall half closure control + layers

- add onewaywall option to create a wall if there is not step back
- add layers of maze
- load minetest scheme .we with onewall option

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

@@ -15,6 +15,7 @@ public class MazeSettings extends JPanel {
     JTextField textHeight = null;
     JTextField textDepth = null;
     JTextField textSeed = null;
+    JCheckBox onewaywallCB = null;
 
     // TODO set width and height and depth of maze with gui
     public MazeSettings(MazeParams params) {
@@ -53,6 +54,8 @@ public class MazeSettings extends JPanel {
             textSeed = new JTextField( "" + params.getSeed(),16);
             add(seedLabel);
             add(textSeed);
+            onewaywallCB = new JCheckBox("one way wall", false);
+            add(onewaywallCB);
         }
     }