redundant (same name, different net). Previously, the method was
to keep the first such node and ignore all others except to add
their resistance and capacitance to the original node. This
prevented routines like "def write" from enumerating all nets
unless they had unique names. The new method keeps the additional
records including the node location where they can be found by
EFNodeVisit(), but flags them with EF_UNIQUE_NODE so that routines
like ext2spice or ext2sim can choose to ignore them. This implies
that this method could be used to reimplement "extract unique"
within "ext2spice" or "ext2sim" without altering label text. This
has not yet been implemented.