If a node is part of a subcircuit, exposed to the parent circuit

If a node is part of a subcircuit, exposed to the parent circuit
through the argument list, but it is not connected in the parent,
then internally designate the node within the subcircuit still
based on the port name (not what it maps to, because it maps to
a floating "node" name), hierarchically nested. The previous fix,
where all "floating" nodes are ignored, ignored this possibility,
leaving way to many pins unconnected. Now that should be fixed,
with sane node names to boot (instead of serially-generated N__*).