Remove traces of mm.musicbrainz.org.

See
http://chatlogs.musicbrainz.org/musicbrainz-devel/2014/2014-11/2014-11-02.html#T01-18-50-32205
Use HTTPS for musicbrainz.org.
Resolve musicbrainz.org/{bare/cdlookup.html -> cdtoc/attach} redirect.
Resolve musicbrainz.org/doc/ redirect.
Merge pull request #97 from Freso/update-mb-urls

Update MusicBrainz URLs