struct for Move

I replaced my Move class by a IMove interface and made a struct implementation for it.

Its kind of an int wrapper although a bit more luxurious since I can call methods directly on it.

    public interface IMove
    {
        int from { get; }
        int to { get; }
        bool isPromotion { get; }
        bool isCapture { get; }
        char capturedPieceType { get; }
    }

Perft 6 improved to 73.8 seconds (where Crafty uses 6.23 second). "Only" a factor 10 left to go!