Index Extension - Fix backward compatibility
Date and Index Extension Fixes

Addressed observations made by Дилян Палаузов
Update docs and bump bytecode version.
Ensure MessageAppend and FlagsSet/FlagsClear have access to the username triggering the action
Enhance SSL/TLS configuration options, and apply further enhancements
from #2642 (Goetz Babin-Ebell) and #3119, #3133 (Duncan Gibbs)

Changed settings:

    ldap_tls_cacert_dir -> ldap_ca_dir
    ldap_tls_cacert_file -> ldap_ca_file
    ldap_tls_cert -> ldap_client_cert
    ldap_tls_check_peer -> ldap_verify_peer
    ldap_tls_ciphers -> ldap_ciphers
    ldap_tls_key -> ldap_client_key

    tls_ca_file -> tls_client_ca_file
    tls_ca_dir -> tls_client_ca_dir

        The paths formerly used as the CA file or directory for client SSL
        certificate verification are now specifically named as such.

    tls_cipher_list -> tls_ciphers

    tlscachedb -> tls_sessions_db
    tlscachedb_path -> tls_sessions_db_path

        While tls_sessions.db is indeed a caching database, consistency
        makes it more transparent what setting applies to what database.

New settings:

    tls_client_cert: <none>
    tls_client_key: <none>

        Client SSL certificate and key to use when cyrus-imapd behaves as
        a client (to other cyrus-imapd server (instances)).

    tls_client_ca_file: <none>
    tls_client_ca_dir: <none>

        Certificate Authority file or directory used to verify client SSL
        certificates.

    tls_client_certs: off|optional|require

        Disable, allow or require clients authenticate with an SSL
        certificate.

    tls_server_cert: <none>
    tls_server_key: <none>

        Server SSL certificate and key to use for connections from
        clients.

    tls_server_ca_file: <none>
    tls_server_ca_dir: <none>

        Certificate Authority file or directory used to verify SSL
        certificates offered by other servers.

    tls_compression: 0

        Enable TLS compression. Disabled by default.

    tls_eccurve: prime256v1

        Select the elliptic curve used for ECDHE.

    tls_prefer_server_ciphers: 0

        Prefer the cipher order configured on the server-side.

    tls_versions: ssl2 ssl3 tls1_0 tls1_1 tls1_2

        Disable SSL/TLS protocols not in this list.

Bugzilla #3822, #3830, #3843, #3861.
Prefix all configuration options related to automatic creation of mailboxes
with autocreate_*.
Fix compiler warnings
Allow suppressing autocreate functionality
Merge #3374 from worldonline/ticket/3374-master
Apply new default for unixhierarchysep (#3682)
Apply new default for expunge_mode and delete_mode (#3684, #3685)
Update the option names in cunit tests as well
From 0d80ef50 by Bron Gondwana: Bug #3390 - add 'proc_path' config variable for proc directory
Issue configuration option deprecation warnings.

Add back the deprecated options to lib/imapoptions, so we can issue the deprecation warnings.
[sieve] fix backward compatibility for sieve index extension

There was a version of the bytecode that had the index extension but did
not update the bytecode codepoints, nor did it increment the bytecode
version number.  We use heuristics to determine if the index extension
support was included in the particular version of the bytecode.

This patch allows usage of these unnumbered versions of bytecode.
Merge branch 'date-extension' into imap4flags-2.5-working

Conflicts:
	sieve/bc_eval.c
	sieve/bc_generate.c
	sieve/bytecode.h
	sieve/sieved.c
Merge remote-tracking branch 'origin/master' into imap4flags-2.5-working