use xml_meta instead of xml_attributes to be more general
use xml_meta instead of xml_attributes to be more general

also adds the relevant metadata for some of the classes

zimmerman-zimmerman/OIPA,zimmerman-zimmerman/OIPA,openaid-IATI/OIPA,zimmerman-zimmerman/OIPA,openaid-IATI/OIPA,zimmerman-zimmerman/OIPA,openaid-IATI/OIPA,openaid-IATI/OIPA,openaid-IATI/OIPA,zimmerman-zimmerman/OIPA