Merge branch 'beta' of git://github.com/metabrainz/musicbrainz-server into beta
Merge branch 'beta' of git://github.com/metabrainz/musicbrainz-server into beta
Merge branch 'mbs5644' of https://github.com/LordSputnik/musicbrainz-server into mbs-5560
MBS-5836: validate entity types against link types in relationship editor

Adds validation to the relationship editor preventing people from
POSTing incorrect entities for a certain link type (e.g. two recordings
linked via "performance of").

Also adds some client-side checks, so that when someone pastes an MBID
for an incorrect entity type into an autocomplete search, it visibly
rejects it (currently, it won't let you submit the dialog anyway, but
the autocomplete still turns green, which is confusing).
Merge remote-tracking branch 'bitmap/mbs-5836' into beta

* bitmap/mbs-5836:
  MBS-5836: validate entity types against link types in relationship editor