Version check

Latest versions of MW have w/maintenance/Version.php, older ones had w/maintenance/version.php and even older had neither, this role should:

1. Check w/maintenance/Version.php and it it doesn't exist go to 2.
2. Check w/maintenance/version.php and it it doesn't exist go to 3.
3. Download a copy of version.php, the URL in the role for this currently needs updating.