Add pattern directed heuristics in order to improve
middlegame and endgame.

Add shogi specific heuristics in order to improve middle game.

Tune weights for positional scoring.

Restrict considered moves at deeper plys.

Improve time usage in order to support xshogi's "fallen-flag"
condition.

Add time usage heuristics which regard that the available time
must be enough to make **all** remaining moves.

Add support for solving tsume shogi problems.

Enable "draw by repitition" detection.
