- list action in ListingController now filters by first letter of last name and defaults to A
- removed some out commented code from ListingController
- changed column expired to version_four since that is what it is really about
- changed model property/getter/setter, tca, sql setup, translation keys and importCerts.php accordingly to match the new column name
- changed the pagination links from jumps to call the controller action using the according letter
- changed the certificate text (in the listing) for certifications that will not expire anymore to be more descriptive
- removed expired/version_four column from searchable columns list