#19 deepCopy() does not handle references correctly

[Massimiliano Zattera]

If we use the CL standard library deepCopy() method on a collection, references
among the objects in the collection are not correctly dealed: if the object a1
and a2, with a2 pointing to a1 are copied, the resulting a3 and a4 should be
such that a4 points to a3, but actually a4 points to a1!

To check this bug, use attached project, implement and run it, then in the
model instance you will find, add a Copy instance to the last item in the table
editor.

That will crate a Copy instance which items are copied form items in the
corresponding Box specified in the copyFrom field for the Copier class.

Basically, three new items are created, but as you can see the new items will
not reference each other, they will reference original items instead.

[Massimiliano Zattera]