re-reading collections from outdated isoreader versions

[sebkopf]

if this can happen automatically on application start, it would be convenient but very slow and without feedback to the user. probably better to implement it in such a way that if someone uses a collection inside the app that has outdated isofiles, ask whether they want to re-read the collection (re-read collection is always an option next to the dropdown and asks whether people want to change read paramters)