Enhancements, possibilities and random ideas
--------------------------------------------

- Support federated IDN domains (??) (Claws Mail itself doesn't support it
  http://www.thewildbeast.co.uk/claws-mail/bugzilla/show_bug.cgi?id=1670)
- Button for checking custom default URL is not 404 (!) check on apply (?)
- Make it run in cache-less mode if cache dir cannot be created (??)
- Only cache "mystery man" once for all hashes (what if changes) (?)
- Cache information label (size on disk/# of avatars/missing cached) (?)
- Empty avatar/missing cache button(s) (?)
- Run network retrieval in a separate thread started at header capture
  hook (??)
- Alternate proxy support (send avatar requests through a proxy which
  is not the one in http_proxy environment variable) (??)
- Limit avatar download size (??) or time (???)
- Configure missing factor/time separately (??)
- Allow changing size of pictures retrieved (while easy on plugin's
  side, this requires changes on Claws Mail itself, so not probably worth
  the effort) (????)

As these are already known, please do not request enhancement bugs for any
of the above unless you have a working patch to be attached to the bug ;-)

Discussion on ML is welcome, specially for items with one or more question
marks.