Changes to the Cyrus IMAP Server since 2.4.17-caldav-beta4

      * Always verify authorization credentials supplied by the client (a
        proxy may be reusing an existing connection as a different user) 
      * Don't bother supporting Digest qop=auth-int since no clients seem
        to use it 
      * Don't show addressbook mailboxes in IMAP LIST output 
      * Plugged leaked memory found by Valgrind 
      * Better handling of request/response bodies 
      * Added httpprettytelemetry option
      * 
      * Added httpallowcors option (Cross-Origin Resource Sharing)
      * 

Changes to the Cyrus IMAP Server since 2.4.17-caldav-beta3

      * Plugged leaked memory found by Valgrind 
      * Rewrote list_feeds() to not use memmem() 
      * OPTIONS method can be used without authentication 
      * Better handling of Connection:keep-alive 
      * Added httpallowedurls option
      * 

Changes to the Cyrus IMAP Server since 2.4.17-caldav-beta2

      * Fixed security bug where a user-agent could access files outside of
        httpdocroot. 
      * Changed annotation entry name scheme to be
