CSV2XL Directive SetBanner

Add new directive SetBanner to CSV2XL 2.1(238):

//XL,SetBanner,text=<banner text>

When set, the banner occupies the first row of the spreadsheet, above the headers, with the text centered in a bold 12 point font. All of the columns are merged so at to make a single wide column for the banner. This is a good way of displaying a spreadsheet title or other identifying information about the spreadsheet, such as dates, selection criteria, etc.

Note that the SetBanner directive, if used, must appear after any AddSheet directive and before the headers. For example:

//XL,AddSheet,sheetname=Frozen,color=COLOR_CORAL_CF

//XL,SetBanner,text=Frozen Aged Inventory as of 09/21/19

Code,Description,Qty,NetWt,0-6,7-13,14-20,21-27,28-34,35+

//XL,SetCol,colfirst=5,collast=10,width=7,formatid=NUMFMT_NUMBER_SEP

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