Added CONTRIBUTORS.txt

Now that Caitlin's Helping, she gets to have some credit
record_almost_* -> record_almost_win_*

Renamed functions for clarity (again)
record_almost_rows -> record_almost_win_rows
record_almost_columns -> record_almost_win_columns
record_almost_diagonals -> record_almost_win_diagonals
record_almost_win_diagonals: comment updates

increased clarity of explanitory comment block
fixed bug in record_almost_win_[rows|columns]

Previously, these functions were potentially recording that
potential n_in_a_row's occurred in the wrong spot. Now this
should be fixed