Make some subitems for discogs, and flesh out artists as an initial test
Check properly for TypeError as well, since that's what's thrown for trying to index an array with a string
Fix failing pep8 test
discogs: expand out label and master subitems too
Yet more error handling
Merge pull request #7 from 96187/master

Extract image URLs from Discogs release data
Whitespace fixes.
discogs: make image extraction work for one image, too
discogs: _uri, not uri
discogs: introduce collect_obj to improve the one-or-many case
discogs: use collect_obj for subitem extraction too
Extract artists