Build 3.5.0.78 of xlsgen adds support for Excel 2003 XML files.

The Excel 2003 XML file format is Microsoft Office's first attempt at saving Excel spreadsheets using XML. They retain much of what makes a spreadsheet, cells, formatting, formulas, a number of rich objects, but they lack some others, most notably charts. In 2006, Microsoft came with a much more mature file format, and that was XLSX files. Nevertheless a number of Excel customers still use this Excel 2003 XML file format because it is much richer and capable than say CSV files. Beginning with build 3.5.0.78 xlsgen can now read such file by just passing the filepath (or memory buffer) in the regular Open() method.