v2.2.19 released

[Timo Sirainen]

http://dovecot.org/releases/2.2/dovecot-2.2.19.tar.gz
http://dovecot.org/releases/2.2/dovecot-2.2.19.tar.gz.sig

* pop3_deleted_flag has been broken since v2.2.10. Using it would
  cause buffer overflows, which could be exploitable. However, this
  bug would have become visible quite soon after users had deleted
  some POP3 mails, because the pop3 processes would have started
  crashing all the time even in normal use.
* "doveadm director flush" command has a changed meaning now:
  It safely moves users to their wanted backends, instead of simply
  forgetting the mapping entirely and leaving the existing connections
  untouched. Use -F parameter to get the original unsafe behavior.

+ Added imap-hibernate processes (see imap_hibernate_timeout setting).
  IDLEing IMAP connections can be hibernated, which saves memory.
+ Optimized tracking mailboxes' vsizes (= sum of all messages' sizes).
  If mailbox_list_index=yes, it's also stored in there. This makes it
  very efficient to look up vsizes for all mailboxes.
+ Added a quota "count" backend, which uses the mailbox vsizes to get
  the current quota usage. It requires using the new quota_vsizes=yes
  setting, which tracks the messages' "virtual sizes" rather than
  "physical sizes". Their distiction is minor and mostly irrelevant
  nowadays (if mail sizes should be counted with LF or CRLF newlines).
+ "doveadm director up/down" commands added. The monitoring script
  should be using these commands instead of changing the vhost count.
  This allows admin to manually disable a server by changing the vhost 
  count to 0 without the monitoring script changing it back.
+ Added support for HAProxy protocol: http://wiki2.dovecot.org/HAProxy
+ Added push-notification plugin framework, which can be used to
  easily implement push notifications to various backends. Implemented
  "ox" backend for notifying Open-Xchange via HTTP/json.
+ imap_logout_format supports more variables now, e.g. number of
  deleted messages.
+ pop3: Added pop3_delete_type setting (related to pop3_deleted_flag).
+ plugin { fts_enforced=yes } setting now fails body searches unless
  it can be done via the full text search engine.
+ Added %{passdb:*} and %{userdb:*} variables to various places
+ auth: Added ":protected" suffix for passdb and userdb fields. If
  used, the field doesn't overwrite an existing field.
+ IMAP/POP3 proxy: If a backend server dies, avoid client reconnection
  spikes by slowly disconnecting clients over time. This is enabled by
  setting login_proxy_max_disconnect_delay=secs passdb extra field.
+ imap: Added new read-only METADATA entries: /private/specialuse,
  /shared/comment, /shared/admin
+ imap: If client disconnects in the middle of a command, log how long
  the command had been running.
- mdbox: Rebuilding could have caused message's reference count to
  overflow the 16bit number in some situations, causing problems when
  trying to expunge the duplicates.
- Various search fixes (fts, solr, tika, lib-charset, indexer)
- Various virtual plugin fixes
- Various fixes and optimizations to dsync, imapc and pop3-migration
- imap: Various RFC compliancy and crash fixes to NOTIFY