[ticket/12831] Optn to prevent setting HTTP headers

https://tracker.phpbb.com/browse/PHPBB3-12831

PHPBB3-12831
[ticket/12809] Fix select button and dropdown list items in RTL.

PHPBB3-12809
[ticket/12809] Remove obsolete rules and selector.

PHPBB3-12809
[ticket/12809] Restore text-align for the pagination.

PHPBB3-12809
[ticket/12671] Possibility to use NOT LIKE expression

PHPBB3-12671
[ticket/12742] Add method for getting authenticated recipients

PHPBB3-12742
[ticket/12742] Add check for empty $users and add method to fitting methods

The method might now return an empty array in case of an empty users array,
too. The notification types then check if the returned array is empty and
return this if it is empty and if the notification types would otherwise
carry out other operations afterwards.

PHPBB3-12742
[ticket/12794] Properly validate google+ field against valid character set

PHPBB3-12794
[ticket/12671] Possibility to use NOT LIKE expression

PHPBB3-12671
[ticket/12742] Replace authenticated with authorised

PHPBB3-12742
[ticket/12742] Remove unneeded sort of users

It doesn't matter which user will get the notification first so we shouldn't
sort the users array.

PHPBB3-12742
[ticket/12671] Possibility to use NOT LIKE expression

PHPBB3-12671
[ticket/12671] Possibility to use NOT LIKE expression

PHPBB3-12671
[ticket/12941] Add sami.conf.php for Travis CI.

PHPBB3-12941
[ticket/12941] Check for Sami parse errors on Travis CI.

PHPBB3-12941
[ticket/12938] Remove the 'Download all attachments' feature.

PHPBB3-12938
[ticket/12943] Add core.phpbb_generate_debug_output core event

Add core.phpbb_generate_debug_output core event to allow extensions
outputting additional debug info.

PHPBB3-12943
[ticket/11528] Revert Mink changes

PHPBB3-11528
[ticket/12949] Check if mime_content_type is actually callable

PHPBB3-12949
[ticket/12742] Add sort options for notification types requiring sorting

PHPBB3-12742