play / detect 2-Fold Rep

[Hai]

It would be nice to have the 2-fold rep option in Stockfish and Komodo too.

1. I have better results when i played a 2-fold rep before i played the best move to win a game.
2. I sometimes have problems to reach move 30 or 40 at time, 2-fold rep can help here very much.
3. When i play with increment 2-fold rep will help me also to reach more time.

This would be really good for our game analysis for strong players.

4. Weaker engines often play a blunder and lost, because they doesn't realise that they are in a 2-fold rep.