TESTS FAIL. Added a TODO note. Also, have verified that 3,3 being cleared of 5 due to pivot Cell 5,7 is also a valid value, so next step is to add that to the test case.
TESTS FAIL. Added a TODO note. Also, have verified that 3,3 being cleared of 5 due to pivot Cell 5,7 is also a valid value, so next step is to add that to the test case.

jkomoros/sudoku,jkomoros/sudoku,jkomoros/sudoku