mergeIndexes() does not work with multiple ranges in each row

mergeIndexes() does not work with multiple ranges in each row.

It collects all of the ranges left to right and top to bottom in colSpans. It then looks through colSpans
consecutively to see if two consecutive ranges span the same columns and are in two consecutive rows. This won't work when you have multiple ranges in one row since they won't be in two consecutive rows.