Additional level filter for completly new material (not studied before)#184

There are many words that I have on level ? which I just cannot remember, but also many that I have never studied. It would be good if completly new vocalbulary, that was never studied had its own level (never studied).

This way I know I have some words I started learning but cannot move to level one, and a group of completly new.

Thank you for the feature request!