This provides an abstraction to the Spreadsheet::WriteExcel module for
easier creation of simple single-sheet Excel documents.

In its most basic form it provides two methods for writing data: write_row and
write_bold_row which write the data supplied to the next row of the
spreadsheet.

However, you can also use $ss->book and $ss->sheet to get at the underlying
workbook and worksheet from Spreadsheet::WriteExcel if you wish to manipulate
these directly.

Author:
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Tony Bowden