equates class "a" in circuit 1 with class "b" in circuit2, and
if circuit 1 has a class called "b" and/or circuit 2 has a class
called "a", then both classes are given a new hash to avoid
conflicts with the (presumably) unrelated cells of the same name
in the other netlist.
been modified in the Tcl/Tk version to take an additional argument
for the file number. In the non-Tcl/Tk-compatibility mode, netgen
should operate in a backwards-compatibility mode with filenum = -1.
Tim Edwards