Update MusicBrainz tag support
Submitted by Frederik 'Freso' S. Olesen
Current MusicBrainz tags are rather outdated. There is GST_TAG_MUSICBRAINZ_TRMID, but MusicBrainz purged TRMs from its database ages ago, being replaced by PUIDs. PUIDs were, in turn, purged from the DB about a month ago, having been superseded by AcoustIDs.
Also, GST_TAG_MUSICBRAINZ_TRACKID does not define Track IDs but rather Recording IDs. Track IDs are being stored in "MusicBrainz Release Track ID" (see https://github.com/musicbrainz/picard/commit/04c30355e2743b7f0bd2cbfce89472483a0d5b85 for MusicBrainz Picard's implementation). (Release) Track IDs were introduced (at the database level) in May this year: http://blog.musicbrainz.org/2013/05/15/schema-change-release-2013-05-15/
Some other MB tags are also missing. I'd suggest the following tags get implemented:
// Core MusicBrainz IDs
// Fingerprinting tags used (past or present) in relation to MB
// Auxilliary tags set by MusicBrainz Picard and/or Jaikoz that are more tangentially MB related