Merge branch 'ticket/13138-2' into ticket/13138-asc

Conflicts:
	phpBB/phpbb/session.php
[ticket/13138] Fix the session key tests

PHPBB3-13138
[ticket/13138] Type hint the variables for IDE usage

PHPBB3-13138
[ticket/13168] Fix mbstring warnings in ACP for PHP 5.6 compatibility

PHPBB3-13168
[ticket/13188] Add missing where clause to post_id query in sphinx index

PHPBB3-13188
[ticket/13188] Correctly format string concatenation

PHPBB3-13188
Merge pull request #3048 from naderman/ticket/13188

[ticket/13188] Add missing where clause to post_id query in sphinx index
Merge pull request #3040 from nickvergessen/ticket/13138-asc

[3.1] Ticket/13138 Only use cookie data when we do not force a user_id

Conflicts:
	phpBB/phpbb/session.php
Merge pull request #3047 from Elsensee/ticket/13168

[ticket/13168] Fix mbstring warnings in ACP for PHP 5.6 compatibility

* Elsensee/ticket/13168:
  [ticket/13168] Fix mbstring warnings in ACP for PHP 5.6 compatibility
Merge branch 'develop-olympus' into develop-ascraeus

* develop-olympus:
  [ticket/13168] Fix mbstring warnings in ACP for PHP 5.6 compatibility
[ticket/13070] Adjust template hook name to match that provided in the class.

PHPBB3-13070
Merge pull request #3050 from prototech/ticket/13070

[ticket/13070] Adjust template hook name to match that provided in the class.