Version 2.0.0 and above:
- Add CRAM-MD5 authentication - done 2.0.10.
- Add rapid 'Authenticate PLAIN <credentials>' auth.
- Add IMAP4rev2 capabilities.

Version 1.3.4 and below:
- Remove dependencies! Get bincimap-updatecache to be
  _as lightweight as possible_.
- Study protocol dump of typical activity. Look for things
  to improve on Binc's output.
- Fix infinite loop when accessing body of message in a
  mailbox that has been deleted.
- Study concurrency, find ways to improve the server.
- Fix --without-ssl
- Default to syslog when logging, except help and version which
  simply use printf.
- Fix I/O timeouts.
- Fix expectAstring()