Chess Offline - Play vs AI

First release.<br><br>- Play offline against a C++ chess engine on three levels: Easy, Medium, Hard<br>- Complete FIDE rules: castling, en passant, promotion, fifty-move rule, threefold repetition, insufficient material, stalemate as a draw<br>- Three board themes, take-back, hints, board flip, move list, captured pieces, optional evaluation bar<br>- Automatic save, PGN export, statistics with an