fix ISO parsing to support gmd:distributorTransferOptions (#238)
fix ISO parsing to support gmd:distributorTransferOptions (#238)

geopython/pycsw,rouault/pycsw,ricardogsilva/pycsw,PublicaMundi/pycsw,kalxas/pycsw,tomkralidis/pycsw,tomkralidis/pycsw,mwengren/pycsw,mwengren/pycsw,tomkralidis/pycsw,ricardogsilva/pycsw,ingenieroariel/pycsw,bukun/pycsw,benhowell/pycsw,ocefpaf/pycsw,geopython/pycsw,kevinpdavies/pycsw,kalxas/pycsw,ocefpaf/pycsw,ingenieroariel/pycsw,geopython/pycsw,ricardogsilva/pycsw,benhowell/pycsw,kalxas/pycsw,PublicaMundi/pycsw,ckan-fcd/pycsw-fcd,rouault/pycsw,ckan-fcd/pycsw-fcd,bukun/pycsw,bukun/pycsw,kevinpdavies/pycsw