[ticket/10729] Update post_edit_user when user being deleted

PHPBB3-10729
[ticket/10729] Update message_edit_user when user being deleted

PHPBB3-10729
[ticket/10729] Fix doc block for user_delete

PHPBB3-10729
[ticket/10729] Add tests for user posts, reports and attachments

PHPBB3-10729
[ticket/10729] Add tests for some special tables with unique conditions

PHPBB3-10729
[ticket/10729] Add assert messages and finish up tests

PHPBB3-10729
[ticket/10729] Ensure that no bans exist before testing create_session

PHPBB3-10729
[ticket/10729] Use mocked null cache for phpunit 3.6 on travis with php 5.2

PHPBB3-10729
Merge pull request #2981 from nickvergessen/ticket/10729

Ticket/10729 Update editor information when user being deleted