[ticket/9758] Adds global template variable CURRENT_USER_AVATAR

PHPBB3-9758
[ticket/9758] Changes class name of new "span" in overall_header.html

PHPBB3-9758
[ticket/9758] Removed useless if-conditions to include functions.php

PHPBB3-9758
[ticket/9758] Error because of missing functions_display.php fixed

PHPBB3-9758
[ticket/9758] Optimises the html code of avatar image in header

PHPBB3-9758
[ticket/9758] Fixed bug in mcp_warn.php

PHPBB3-9758
[ticket/9758] Adding impr. for overall_header display of avatar and username

PHPBB3-9758
[ticket/9758] Removed the needless space after first ENDIF

PHPBB3-9758
[ticket/9758] Adds id and changes filter to fix travis CI test

PHPBB3-9758
[ticket/9758] Slims the line 4775 in includes/functions.php

PHPBB3-9758
[ticket/9758] Remove unnessary if-question for include functions_display

PHPBB3-9758
[ticket/12318] Correctly setup HHVM for functional tests.

PHPBB3-12318
[ticket/12318] Upgrade to a recent stable version of HHVM.

PHPBB3-12318
[ticket/12318] Add PPA providing dependencies for recent HHVM on Ubuntu 12.04.

PHPBB3-12318
[ticket/12318] Always install new config file on HHVM upgrade conflict.

PHPBB3-12318
[ticket/12318] Pin HHVM version to 3.0.0~precise.

PHPBB3-12318
[ticket/12318] Use MySQL instead of MySQLi for now on HHVM.

PHPBB3-12318
[ticket/9758] Clickable avatar in header and renamed class for avatar-img

PHPBB3-9758
[prep-release-3.1.0-b2] Update version to 3.1.0-b2
[prep-release-3.1.0-b2] Add migration for 3.1.0-b2