Shortcut sorting when no move is in history

An alternative algorithm to psqt scoring.

Still unclear what is the best, more tests needed.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/movepick.h

@@ -87,6 +87,7 @@ private:
   int numOfMoves, numOfBadCaptures;
   int movesPicked, badCapturesPicked;
   bool finished;
+  bool All_zero;
 };