Build 4.9.0.17 of xlsgen is a fix pack for issues related to XLSB files.

- under certain circumstances, array formulas were not written correctly and would corrupt the Excel file (XLSB).

- incorrect external reference index when reading from a XLSB file and converting to a XLSX file

- generation of external reference cache when converting a XLSX file to a XLSB file

- internal formula building for a number of conditional formattings when converting a XLSB file to a XLSX file