HPSR-230; HPSR-224; HPSR-146 Converted dc_date and dc_date_created into text fields for capturing verbatim date strings. Added dc_date_createdstandard date field for capturing fields in W3C recommended extended ISO 8601 date format. Added date parsing to DSpace import to convert extended ISO dates, including partial dates and intervals, to Drupal Date module's start and end date type fields.