* develop-olympus:
[ticket/8610] Update comment
[ticket/8610] Do not use requests to submit posts except in posting_test.php
[ticket/8610] Move posting helpers to separate file
[ticket/8610] Create helper functions to create topic/post in functional tests
[ticket/8610] Use phpbb_update_rows_avoiding_duplicates
[ticket/8610] Revert some funky merging I did from rebase
[ticket/8610] Add some comments
[ticket/8610] Update Bookmarks and Subscriptions when splitting topics
[ticket/8610] Update Bookmarks when merging posts into another topic
[ticket/8610] Update Bookmarks when forking topics
[ticket/8610] Update Bookmarks when merging topics