outelem = clone(inelem)
creates a circuit element, outelem, with
identical properties as inelem. The clone
does not copy information about the parent circuit such as
ParentNodes and
ParentPath.
outckt = clone(inckt)
creates a circuit object, outckt, identical
to inckt. Circuit elements in the
inckt are cloned recursively and added
to the same nodes in the outckt. The ports or
terminals in the outckt are defined same as
inckt.