lib-sieve: vnd.dovecot.duplicate extension: Only track duplicate when Sieve script executes successfully.

Forgot to initialize variable, causing a segfault at runtime.

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.

Forgot to skip line upon error.

Added means to log user errors/warnings as info in master log.
Previous change was inadequate because an error was still logged.

Prevents administrator frustration about useless log messages caused by users with too much mail.

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

This was broken by the ld.gold fix.

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

Before, sievec and sieve-dump would switch to mail_uid:mail_gid and then fail to compile/dump a root script.

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

lib-sieve: increase action instance count (for limit checking) only when an action is actually created.

Added test for interaction between include extension and dict script location support.

Sieve script equality function implementation was wrong.

Patch by Eray Aslan.

Patch by Timo Sirainen.

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.