[ticket/11366] Update var names

PHPBB3-11366
[ticket/11366] Update FILE_NOT_FOUND language string

This var is always used with a colon.

PHPBB3-11366
[ticket/11366] Fix whitespaces

PHPBB3-11366
[ticket/11366] Update FILE_NOT_FOUND language string

PHPBB3-11366
[ticket/11366] Force the use of the cache on the list page

PHPBB3-11366
[ticket/11366] Add recheck-all link

PHPBB3-11366
[ticket/11366] Use force_cache on the list page

PHPBB3-11366
[ticket/11366] Add $config['extension_force_unstable']

PHPBB3-11366
[ticket/11366] Move "recheck all" link

PHPBB3-11366
[ticket/11366] Better language string for "recheck all"

PHPBB3-11366
[ticket/11366] Versions, options and actions heading should be centered

PHPBB3-11366
[ticket/11366] Hide the version check settings by default

PHPBB3-11366
[ticket/11366] Move the links to the top of the page

PHPBB3-11366
[ticket/11366] Remove the extra {S_FORM_TOKEN}

PHPBB3-11366
[ticket/11366] Exchange links and settings' form

PHPBB3-11366
[ticket/11366] Fix HTML

PHPBB3-11366
[ticket/11366] Add config value in schema_data.sql

PHPBB3-11366
[ticket/11366] Fix headings css in list page

PHPBB3-11366
[ticket/11226] Explicity set file_moved to false

PHPBB3-11226
[ticket/12611] Remove phpBB Group copyright notice from .gifs

PHPBB3-12611