lib-sieve: Made sure local part of a mail address is encoded properly using quoted string when it is not a dot-atom.

lib-sieve: Allow X-Original-To header for the address test.

Trace_log variable was not initialized.

This way, imapsieve can show to which user.mailbox.uid the trace applies.

Registering conflicting commands before conflicts are checked is a bad idea.
Make sure conflicting extensions are not part of remaining validation process.

This was duplicated between the lda-sieve and imapsieve plugins.

lib-sieve: Implemented support for writing runtime trace output to a directory if it exists, much like Dovecot rawlog.

doc/example-config: Added description for a few generic settings that were only mentioned in the INSTALL file.

Futher changes are needed to prevent accessing the envelope in the first place.

It allows sending feedback report (RFC 5965) messages.

lib-sieve: Notify extensions about whether they are loaded in the validator optionally (ihave extension).

Conflicts are now always tested from both sides. This is mainly important for the "ihave" test.

An earlier change exposed this bug. Before, it was always a socket, and closing the output early meant using shutdown() rather than close().
This bug caused an assert failure.

lib-sieve: Renamed sieve_runtime_flags to sieve_execute_flags and made these available to result execution.

lib-sieve: util: Fixed message header composition functions to turn newlines into proper header line continuations.

lib-sieve: redirect action: Made mail loop detection more robust by forcibly adding a Message-ID header if it is missing.

Struct mail_vfuncs has an additional method now.

This is needed for other extensions that manipulate flags while the imap4flags extension is not used directly.