ListHandle bugfix

[bero]

When ObjectReference/SingleLink is passed to TBoldAbstractListHandle.SetCurrentElement it uses owning object instead of other end.

Change it so that other end is used as is logical.

Example

lhaAddress.CurrentElement := aPerson.Address;

aPerson.Address is a singlelink (BoldObjectReference) and assigned to BoldListHandle currentElement.
It should not use BoldObjectReference but BoldObjectReferences BoldObject instead