mbs-6201: add event collection support to the xml ws
Show collection types on the WS
Merge branch 'schema-change-2014-q4' of https://bitbucket.org/metabrainz/musicbrainz-server into events-webservice
move type to be an attribute for consistency
Merge remote-tracking branch 'reosarevok/events-webservice' into schema-change-2014-q4

* reosarevok/events-webservice:
  move type to be an attribute for consistency
  Show collection types on the WS
  mbs-6201: add event collection support to the xml ws