fix resize issues

Board
    - build possible attacks List<GridPoint2>
    - build possible assits List<Pawn / GridPoint2>
    - support Orientation offset
    - support inverted even/odd row scheme

Tile
    - automatic overlays to show unit stack depth

Pawn
    - public abstract boolean isUnit(); => unit stack depth

might think about decorator pattern for overlays



us decorator pattern, No can Do ??

    + interface Pawn

    + !!! abstract class SimplePawn implements Pawn
        protected Image OR extends Image

    + abstract class PawnDecorator implements Pawn
        potected Pawn pawn;
        PawnDecorator(Pawn pawn) { this.pawn = pawn; }
        public _method_() { pawn._method_(); }

    + ?! abstract class OverlayPawnDecorator extends PawnDecorator
        ...
    + ?! abstract class HeadedPawnDecorator extends PawnDecorator
        ...

    * class Unit extends SimplePawn
        getUnit(_args_) {
            return new HeadedPawnDecorator( new OverlayPawnDecorator ( new Unit(_args_) ) )
        }