[ticket/12275] Fix a bug on the event "core.modify_username_string"

Call the event "core.modify_username_string"
also if $mode is "colour", "username" or "profile".

PHPBB3-12275
[ticket/12384] Run Travis CI HHVM tests against MySQLi instead of MySQL.

HHVM MySQLi has been fixed and works for us now.

PHPBB3-12384
[ticket/12407] Allow changing of post_data, etc. at end of posting.php

The current event core.posting_modify_template_vars is just ran using dispatch
but it doesn't pass any data from posting.php to the listener. Because of that,
it's not possible to know anything from posting.php and therefore limits the
use cases of this event. This will change it to allow similar actions as with
the event core.modify_posting_parameters.

PHPBB3-12407
[ticket/12407] Add message_parser as passed variable to event

PHPBB3-12407
[ticket/12275] Change if (empty) to if (!isset)

PHPBB3-12275
Merge branch 'develop-ascraeus' of https://github.com/phpbb/phpbb into ticket/12407

Conflicts:
	phpBB/posting.php
[ticket/12407] Assign template variables again after merging develop-ascraeus

PHPBB3-12407
[ticket/12407] Merge @change in doc block of event

PHPBB3-12407
[ticket/12332] Fix displaying attachments with long file names

PHPBB3-12332
[ticket/12025] Post Preview no longer shows warnings

https://tracker.phpbb.com/browse/PHPBB3-12025

PHPBB3-12025
[ticket/12185] Fixing the width of topic header for translation.

PHPBB3-12185
[ticket/12332] Remove width sizing, as it is already set

PHPBB3-12332
[ticket/12332] Accomplish all word creaking in template and CSS

PHPBB3-12332
[ticket/12332] Add break-word to fixed width table CSS

This ensures long words break and remain within the table cell

PHPBB3-12332
[ticket/12332] Restore some changes back to original state

PHPBB3-12332
[ticket/12332] Adjust column widths for responsive changes

PHPBB3-12332
[ticket/12332] Adjust size of mark column where too wide

PHPBB3-12332
[ticket/12025] Don't show any error on preview if the message is empty

PHPBB3-12025
[ticket/12025] Fixing the condition....

PHPBB3-12025
[ticket/12332] Add missing semicolon to inline styling

PHPBB3-12332