api: Add test coverage for registration.
api: Fix error on drinks/ on empty system.

Closes #233.
Add custom file storage class to return absolute URLs.

Issue #232.
Twitter: Don't post guest tweets.

Issue #231.
Twitter: use string pathname.

Tweepy chokes on unicode path names.

Issue #232.
Fix missing import
Bump pytz dependency.
Fail silently on errors sending e-mail.
Always check media URL.