Refinements/enhancements to the //XL, AddSheet directive. It is now possible to create a multi-sheet workbook with heterogeneous pages by essentially appending multiple sections in a single CSV, with each section consisting of:
//XL,AddSheet,sheetname=...
<header line>
<data lines>
<data lines>
...
The initial AddSheet directive at the start of the file is optional and mainly serves to establish a sheetname other than the default "Data". Subsequent AddSheet directives terminated the existing sheet (triggering totals if applicable), and then starts the new sheet, which includes re-analyzing the columns to establish new formats. Note that any explicitly set column formats are reset by the subsequent AddSheet directive, but the general header formatting attributes, including the ColTitleTextRegex setting in the INI file are reapplied to each new sheet.
