[Dovecot] v2.2 status update: IMAP NOTIFY extension and more

[Timo Sirainen]

v2.2 hg now has support for NOTIFY extension. The only thing missing is
support for SubscriptionChange events. Now would be a good time for IMAP
clients to start implementing and testing it. :) I remember K9
developers at least said they were just waiting for Dovecot to support
it first.

v2.2 implements some other extensions also: BINARY, CATENATE and MOVE.
Stephan has also implemented URLAUTH pretty far. Hopefully it gets
finished in time for v2.2.0. I'll also try to implement the rest of the
LEMONADE extensions: CONVERT, CONTEXT=SORT and URLAUTH=BINARY.

I'm also considering implementing an SMTP submission server, which works
only as a proxy to the real SMTP server. The benefits of it would mainly
be:

 * It could support BURL command and other extensions required by
LEMONADE. The real SMTP server would see only regular DATA commands.
 * Would make SMTP AUTH easy to implement regardless of what the real
SMTP server is.