Add metadata schema identification/systemId/@type='gbc' and 'idGBC' metadata key
Add metadata schema identification/systemId/@type='gbc' and 'idGBC' metadata key for audio
Text and Audio schemas and example metadata.xml files updated with uid attributes. https://trello.com/c/PgJZNIvV
Add metadata key idBiblica for identification/systemId/@type='biblica'. https://trello.com/c/O7d9PSOw
Merge remote-tracking branch 'origin/master' into gh-pages
push rng schema updates