Implement negation of query filter closer to underlying API. Previously andNot() negated the whole filter and it's usage in IsUnique was actually a misunderstanding. Having not() as in javax.persistence.criteria.Predicate seems to be more intuitive for negating the whole filter and more flexible.

{
    "land.zusatz_wert": [{
        "id": 1000,
        "probe_id": 1000,
        "pzs_id": "A77",
        "messwert_pzs": 12.0,
        "messfehler": 8.0,
        "nwg_zu_messwert": 3.0,
        "letzte_aenderung": "2012-05-08 14:00:00"
    }]
}