Bank Export event scripts; ISBankExportLine now includes a Parent property

ISBankExportLine now includes a Parent property, returning the ISBankExport that it is part of.

This can be used in the Bank Export event script to access properties of the parent object.

In addition, a Tag property has been added to the ISBankExport object - this may be useful in scripting.

Note, scripts that create ISBankExportLine objects should now use ISBankExport.CreateBankExportLine function.