v2.2.0

Fixed:

• PIL.Image.open'ed files weren't closed, #390
• resolver: if mets_url is relative path, resolve before anything else, #319, #397
• Resolver.workspace_from_url: Create dst_dir before resolve for py <= 3.5, #330, #393
• fix help string for -m/--mets, fix #263, #391

Changed:

• downgrade filegrp syntax errors to warnings, #364, #389