All locally created nodes (CKTmk..() invocations in XXXsetup())
must be deleted in XXXunsetup()
Otherwise CKTmk..() invocations during a following CKTsetup()
will re-emit still used node numbers,
thus accidentally shorting nodes.
This patch fixes the complex cases,
which are external node variables (ports of the instance),
which might be moved over to other external node variables
to cope with optional port connections.
This is fixed by copying the node numbers to local shadow variables
to avoid messing with the external nodes.
Otherwise a following CKTsetup() might again meddle with the external
node variables, at least causing considerable confusion, probably causing
hard to find bugs.
rlar
0e9576cb34