refactoring, deploy Position and XYGridIterator

- try to use more Position instead of (x,y)
  - create PositionWithDpeth for its specific usage in path finding
- create a XYGridITerator that walk cells from grid X then Y.

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

@@ -0,0 +1,19 @@
+package org.artisanlogiciel.games.maze.gui;
+
+import org.artisanlogiciel.games.maze.model.WidthHeightProvider;
+
+import javax.swing.*;
+
+public abstract class CellGridComponent
+extends JComponent {
+
+    MazeCellRenderer cp;
+
+    MazeCellRenderer createCellRenderer(boolean hexagon, WidthHeightProvider model, WidthHeightProvider frame)
+    {
+        MazeCellRenderer cellRenderer = hexagon ?
+                new HexagonCellRenderer(model, frame, 0, 0)
+                : new MazeCellRenderer(model, frame, 0, 0);
+        return cellRenderer;
+    }
+}