[ticket/12589] Search directly in $directory if it's an absolute sub-path

PHPBB3-12589
[ticket/12589] Fix tests

PHPBB3-12589
[ticket/12589] Add test searching in a non absolute directory

PHPBB3-12589
[ticket/12641] Use jQuery's trim() method. IE8 does not support the native one

PHPBB3-12641
[ticket/12610] Add command to check if the board is up to date.

PHPBB3-12610
[ticket/12610] Add test for the base case

PHPBB3-12610
[ticket/12610] Add options to update check command.

PHPBB3-12610