human-readable errors in read() and write()
merge
changelog thanks for discogs plugin (#283 / #210)
only IOErrors are IOErrors
discogs: tweak colorization & installation docs

I thought having "MusicBrainz" colored green was a little distracting since
it's the common case (and universal without the discogs plugin), so this just
makes it neutral-color in that case.
discogs: expand docs ever so slightly
don't penalize Discogs matches for lacking MBIDs

This removes the distance component for MBIDs for matches that don't have
MBIDs. (Previously, when importing an album that already has MBIDs, Discogs
would be unfairly penalized.)
different paths for convert

the paths configuration for converted files can be different from the importer
closes #232
docs for the convert pathformat configuration
remove beets==dev URL

This is going away with PEP 438.
fix some debug code
Merge pull request #285 from duailibe/convert_path

Different paths for convert
docs/changelog for convert paths config (#285)
Abstract method to determine if track number has changed.

This is a little more accurate than the previous method (check if track
is in index or medium_index) by looking at the `per_disc_numbering`
setting and comparing the index or medium index accordingly.

It's also a little more accurate in the display output by diffing the
combined `disc-track` to `medium-medium_index` (if using per disc
numbering) and intelligently colorizing the either the whole track
number or just the suffix.
Don't colorise the "()" around partial match text. For consistency (and a little easier to read?)
Indent album title and artist when there are no changes for consistency with when there are (and easier to read?)
Display album ambiguation on info line (after similarity and source). Colorise disambiguation light grey for subtle distinction from album text.
Colorize benign track index changes (to/from per disc numbering) in yellow.
No penalty for track index changes to/from per disc numbering.
Colorize parenthesis around partial match message.