Merge ommitted stuff from mail/dovecot package, most importantly the
dovecot-sieve option (managesieve support is now included with sieve).
Create additional "dovenull" user for login processes.  Add MESSAGE
with upgrade notes.  Grab maintainership.

Major changes since 1.2:

* Dovecot uses two system users for internal purposes now by default:
  dovenull and dovecot. You need to create the dovenull user or change
  default_login_user setting.
* Global ACLs are now looked up using namespace prefixes. For example
  if you previously had INBOX. namespace prefix and a global ACL for
  "INBOX.Sent", it's now looked up from "INBOX.Sent" file instead of
  "Sent" as before.
* Maildir: File permissions are no longer based on dovecot-shared file,
  but the mailbox directory.

+ Redesigned master process. It's now more modular and there is less
code running as root.
+ Configuration supports now per-local/remote ip/network settings.
+ dsync utility does a two-way mailbox synchronization.
+ LMTP server and proxying.
+ Added mdbox (multi-dbox) mail storage backend.
+ doveadm utility can be used to do all kinds of administration
  functions. Old dovecotpw and *view utilities now exist in its
  subcommands.
+ imap and pop3 processes can now handle multiple connections.
+ IMAP: COMPRESS=DEFLATE is supported by imap_zlib plugin
+ director service helps NFS installations to redirect users always
  to same server to avoid corruption

(ghen)