Fix#1395, a 2020 issue which had been marked stale and is now re-opened. Static valueBinder property of Cell isn't ideal. It would be more flexible to make it a dynamic property of the spreadsheet. Static property will continue to be used, but dynamic property will be used first if it is set. Readers will also be changed to add a valueBinder property which they pass to the spreadsheet; however, it will make a difference only for Csv/Html/Slk, since the other readers use setValueExplicit which ignores valueBinder.
Documentation is updated in several places to note that dynamic property is preferred over static.
oleibman