[barcode_scanner] Add detection confidence level to edit & log messages
[barcode_scanner] Try to scale image to different resolutions, often helps with too detailed scans
[barcode_scanner] Add quality (confidence) threshold
[split_artists] Better display of track/recording ref counts, other output improvements
[split_artists] Also fix alternate artist credits, not just primary

Migration SQL:

-- SET search_path=mbbot,musicbrainz;
DROP INDEX split_artists_history_artist_bot_version_time_idx;
ALTER TABLE split_artists_history ADD COLUMN credit int;
-- Previously we only looked at credits where artist.name=credit.name
-- Can't figure out credits for all rows, but we don't care about artists/credits that have disappeared
UPDATE split_artists_history sah SET credit=ac.id
    FROM artist_credit ac
    JOIN artist_credit_name acn ON (ac.id=acn.artist_credit)
    JOIN artist a ON (acn.artist=a.id)
    WHERE sah.credit IS NULL
      AND sah.artist=a.id
      AND ac.name=a.name;

VACUUM FULL split_artists_history;
CREATE INDEX split_artists_history_credit_bot_version_time_idx
    ON split_artists_history(credit, bot_version, time);
[split_artists] Add more split phrases
[discogs_cover_art] Simplify usage, make many dependencies optional

* Make Amazon/Spotify/iTunes modules optional
* Don't require mechanize patch (use monkeypatching)
* Don't hardcode mbbot schema
* Make config_caa.py config optional
[barcode_scanner] Change edit note text, add low/medium/high quality rating
[barcode_scanner] Try fewer scales, break early on low resolution
[split_artists] Port to 2013-05-15 schema change, see MBS-5528, MBS-1839
Merge pull request #5 from intgr/master

Barcode scanner, split_artists & discogs_cover_art updates