WertMengeArt vs Messwertstatus

[hf-mrdachner]

The non-official Enum WertMengeArt corresponds to the official Messwertstatus except the value ANGABE_FUER_LIEFERSCHEIN is missing.
The library should incorporate the offical enum.

[hf-kklein]

@hf-mrdachner is this fixed in #201