Business layer finBL.FormatDateDocuments function returns "30 December 1899" from VBA

The business layer finBL.FormatDateDocuments function returned a date of "30 December 1899" if a null date, E.g., a finClient.DateOfBirth with a value of Nothing was passed to it.

This function has been updated to add a new optional parameter (True by default), to treat COM Dates with a value of Zero as blanks.

This overcomes the issue in which COM dates are treated differently to .NET dates.