issue #63: dateSingle and dateRange
issue #63: dateSingle and dateRange

changed relationDate to dateSingle and relationDateRange to dateRange

informaticmonad/EAD3,SAA-SDT/EAD-Revision,SAA-SDT/EAD3,informaticmonad/EAD3,SAA-SDT/EAD-Revision,SAA-SDT/EAD3