Backwards compatibility is provided for vnd.dovecot.duplicate.
Still need to fix the constraint that it must not track duplicates from failed Sieve executions.

doc/extensions/spamtest-virustest.txt: Clarified that these extensions use the extended POSIX regular expressions.

Use sieve_vacation_send_from_recipient to enable this behavior.
Documentation in doc/extensions/vacation.txt is updated.

It is still a plugin, but no longer a separate package.

It is now possible to track duplicates based on arbitrary headers or even arbitrary string values using the new :header and :value arguments respectively.
The experation time can be configured using the new :seconds argument.
This change is backwards compatible as long as the name argument wasn't used. This is now a :handle <handle> argument.

Change backported from Pigeonhole v0.4 tree, which means that this change will duplicate there upon merge.

Added support for the :optional tag of the include command.
Changed Sieve script API in the process; opening the script is now available as a separate step.

sieve-refilter: improved man page documentation by explicitly specifying the syntax used for mailbox arguments.

Also fixed a small mistake in the spefication for the vnd.dovecot.duplicate extension.

This currently breaks uninstall when the settings plugins are removed and 20-managesieve.conf
remains in conf.d directory. These sections only need to be active in the config file when settings
for the services themselves need to be disabled.

Incorporated sieve_duplicate plugin into main Pigeonhole tree as a normal extension (vnd.dovecot.duplicate).
Also restructured doc dir a bit in the process.

Additional paths are specified by adding a sequence number (starting at 2) to the setting name.
Added support for specifying home-relative paths for sieve_before and sieve_after.
This enables administrators to specify user-specific global Sieve scripts that cannot be viewed or changed by virtual users.

  - Built generic interface for alternative script sources.
  - Implemented dict script location.
  NOTE: ManageSieve will not work with this yet, nor will sieve_before/sieve_after.

Old name is now deprecated.
Support for the even older global_script_path name for this setting is dropped.

Setting sieve_max_redirects=0 now means that redirects are prohibited rather than unlimited.
Now there is always a limit, but it can be enormous if the administrator wants to.

- Now compiles regularly without --with-unfinished-features
- Still experimental though, so be careful.
- Changed command structure a bit, removing the useless -M option.

- Updated documentation.
- Made editheader extension disabled by default

lib-sieve: vacation extension: finally added support for using the original recipient in vacation address check.