This trait class is temporary, we may switch to interfaces later.
this trait class extends erp entities with getReferenceData().
this must be used wherever an erp is to be stored in extra data.

related: pcsg/buero#416

related: pcsg/buero#419

related: pcsg/buero#427

ERP entities can now say whether they can be copied. There is therefore a central copy dialogue.

Example: {erpGetPrefixedNumber assign=prefixedNumber var=$erpUUID}

related: brassberg/ecoyn/tickets#83

Dev archive

See merge request !99

Dev

See merge request !96