Missing features that might break stuff

• track: handle multi-artist albums when creating one during track edition
  "16 pièces" by Hocus Pocus might be a good album to try this on: auto metadata only created 2 albums (1 by Hocus Pocus, 1 by multi-artist / undefined)
• artist: rename
  "Hiromi" might be a good artist to try this on: auto metadata finds her Japanese name, we'd like it to be in english (we should work on "renaming artist", but we also might want to look into collected metadata to see if there isn't a "other names" field somewhere)

Missing track edit features that we can be chill about

• selecting a cover will lock it, add checkbox to unlock it
• add possibility to select multiple artists (feats)
• handle multi-artist albums when assigning tracks to existing album (turn single-artist album into multi-artist)? This might not be useful very often as automatic metadata is usually pretty good and manual edition is just for minor hiccups.
• add / remove genres (creation possible)