Chess Sudoku King Knight Queen

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Hundreds of new puzzles: Classic, King, Knight Sudoku.
New mode: Queen Sudoku.
Rule: Place numbers in the grid such that every row, column and 3x3 box contain the numbers 1 to 9. One number (9) in the grid is a chess Queen. Two Queens cannot be placed along the same row, column or diagonal of any length.
Fix issues with check result feature.