MBS-6395, call DurationLookup->update() on medium insert + add test.
MBS-6395, Also update medium_index table when Edit::Medium::Edit makes changes to tracks.
MBS-6395, correctly deal with discs on which some tracks have a length, but not all.
MBS-6395, remove unneccesary 'use Try::Tiny' line.
MBS-6395, Move DurationLookup->update() calls into Data::Track.
MBS-6395, don't try to get track.medium from deleted tracks.
MBS-6490: limit browse requests to actually loading only 500 results at a time, so as to not break the DB server
MBS-6490: make number of inital pages consistent by loading 2000 results
MBS-6490: don't change find_by_name_prefix semantics, just use two queries
MBS-6446: consider definedness, not truthiness, of $username when validating the user registration form
MBS-5625: remove excess spaces from relationship display
MBS-5625: remove a bunch of [%%]
MBS-3618: set maxlength on RE 'add tracks' field
MBS-6490: move query_to_list_limited to generally use a fancy double-query
MBS-6490: fix up tests
Merge branch 'beta' of https://bitbucket.org/metabrainz/musicbrainz-server into mbs-6584
mbs-6584: removing unused code from controllers
MBS-6469: Allow creating example relationships without a name

Removes the Javascript check that the name field is not empty,
in order to allow editors to document example relationships
without having to give them a name.
MBS-6496: Do not use medium recordings when adding new discs in release editor

When a new disc is added in the release editor, the last disc in the
editor is cloned and all its fields are cleared. However, there
appears to be a slight mistake in this clearing - the 'id' field is
cleared twice.

I've changed the second reference to the 'id' field to
'medium_id_for_recordings', which is an id that is used to provide
recording association suggestions. Clearing this, the release
editor suggests that new recordings are created.
Fix up FixTrackLength.pl script for the schema change two months ago.