Fixed it so that nakedSubset will do a usefulness check. In practice we aren't seeing any other technqiues that return non-useful things, although I'm sure there are some.
Fixed it so that nakedSubset will do a usefulness check. In practice we aren't seeing any other technqiues that return non-useful things, although I'm sure there are some.

jkomoros/sudoku,jkomoros/sudoku,jkomoros/sudoku