[ticket/11749] PHP Events for search.php

PHPBB3-11749
[ticket/11749] PHP Events for viewforum.php

PHPBB3-11749
[ticket/11749] Template events for topic_list_row_pre/append

PHPBB3-11749
[ticket/11749] Move event after all template data has been defined

PHPBB3-11749
Merge pull request #1619 from VSEphpbb/ticket/11749

[ticket/11749] PHP and Template Events for Topic Preview Extension