Bug 15170 - Add 264 field to MARC21*DC.xsl

 Bug 15170 - Add 264 field to MARC21*DC.xsl

Modify MARC21*DC.xsl to add RDA 264 field

To test:
- Copy from LOC z39.50 the Maxwell's handbook for RDA (ISBN
  9780838911723)
- Look the field 264 in framework, save record
- Open this URL in OPAC

  /cgi-bin/koha/unapi?id=koha:biblionumber:41201&format=marcxml

  And play with id (the number of new record for Maxwell book) &
  format parameters
  Test format=rdfdc, format=srw_dc and format=oai_dc
- Notice that <dc:publisher> and <dc:date> are not present
- Apply this patch
- Reload the URL for the three formats
- You will see the tags publisher and date are taken from 264

Signed-off-by: Frédéric Demians <f.demians@tamil.fr>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>