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

PHPBB3-9758
Merge remote-tracking branch 'crizz0/ticket/9758' into develop-ascraeus

* crizz0/ticket/9758:
  [ticket/9758] Clickable avatar in header and renamed class for avatar-img
  [ticket/9758] Remove unnessary if-question for include functions_display
  [ticket/9758] Slims the line 4775 in includes/functions.php
  [ticket/9758] Adds id and changes filter to fix travis CI test
  [ticket/9758] Removed the needless space after first ENDIF
  [ticket/9758] Adding impr. for overall_header display of avatar and username
  [ticket/9758] Fixed bug in mcp_warn.php
  [ticket/9758] Optimises the html code of avatar image in header
  [ticket/9758] Error because of missing functions_display.php fixed
  [ticket/9758] Removed useless if-conditions to include functions.php
  [ticket/9758] Changes class name of new "span" in overall_header.html
  [ticket/9758] Adds global template variable CURRENT_USER_AVATAR