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/LabyLayers.java

@@ -0,0 +1,25 @@
+package org.artisanlogiciel.games.maze;
+
+import org.artisanlogiciel.games.minetest.Range;
+
+import java.util.HashMap;
+
+public class LabyLayers
+extends Range
+{
+    HashMap<Integer,LabyModel> layers = new HashMap<>();
+
+    public LabyLayers()
+    {
+        super();
+    }
+    public void addLabyModel(int z, LabyModel model)
+    {
+        layers.put(new Integer(z), model);
+    }
+
+    public LabyModel getLayer(int z)
+    {
+        return layers.get(new Integer(z));
+    }
+}