prepare for hexagon display & other models

- display cell as hexagon is Display.mHexagon if set ( not default )
will need a checkbox to set this
- various new models preparation...

java/org/artisanlogiciel/games/maze/model/HalfSquareRasterModel.java

@@ -16,11 +16,13 @@ import org.artisanlogiciel.games.maze.WallsProvider;
  * bit value :
  * - set : there is a wall , no move in that direction
  * - unset : move is possible , there is no wall
+ *
  */
 public class HalfSquareRasterModel
     implements WallsProvider,
         MovesProvider,
-        WidthHeightProvider
+        WidthHeightProvider,
+        HalfSquareProvider
 {
     int LEFT = 0x01;
     int DOWN = 0x02;
@@ -42,7 +44,16 @@ public class HalfSquareRasterModel
         this.width = width;
         this.height = height;
 
-        lines = new long[height][(BITSX * width)/USED_BITS];
+        lines = new long[height][getLongs()];
+    }
+
+    public int getLongs()
+    {
+        return (BITSX * width)/USED_BITS;
+    }
+
+    public long[][] getLines() {
+        return lines;
     }
 
     public void setLeftDown(int x, int y, short moves)