Various forum fixes from 13.x - part 5 (avatars)
[bp/r52741][FIX] forums: Use modifier avarize as tiki-show_user_avatar.php is buggy and doesn't support static avatars 
[bp/r52742][FIX] forums: Use modifier avarize as tiki-show_user_avatar.php is buggy and doesn't support static avatars (missed some)

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@52751 b456876b-0849-0410-b77d-98878d47e9d5