This update provides version 2.4.18 of cyrus-imapd

* Security fix: handle urlfetch range starting outside message range
* A bunch of cleanups and fixes to compiling
* A bunch of sieve cleanups
* Enhanced SSL/TLS configuration options
* Disable use of SSLv2/SSLv3
* Allow SQL backend for mboxlist and statuscache (thanks Julien Coloos)
* Fixed T116: correct LIST response for domains starting with 'inbox.'
* Fixed T76: fixed lmtpd userdeny db checks (thanks Leena Heino)
* Fixed bug #3856: lmtpd now performs userdeny checks
* Fixed bug #3848: support charset aliases in encoded headers
* Fixed bug #3853: disconnect_on_vanished_mailbox: release mailbox lock before exiting (thanks Wolfgang Breyha)
* Fixed bug #3415: fixed nntpd LIST/GROUP bug
* Fixed bug #3784: no longer crash in THREAD REFERENCES when messages reference themselves
* Fixed bug #3757: don't segfault on mailbox close with no user