* ticket/8319:
[ticket/8319] Do not repeat the replacement
[ticket/8319] Add explanation for RELATIVE_URL and update LOCAL_URL
[ticket/8319] Update BBCodes that currently use the LOCAL_URL tag on update
[ticket/8319] Add new token RELATIVE_URL to allow foreign relative URL parts
[ticket/8319] Prepend Board URL to LOCAL_URL links to prevent abuse
Conflicts:
phpBB/install/database_update.php