comparisons between, duplicate cells (cells with the same netlist
that may have more than one name in a circuit, or which for some
reason appear with the same name more than once in a netlist).
Added more checks to the list prematching, which prevents various
troubles with cells having a mismatched hierarchy. Added a
command option to "flatten class" to flatten instances only within
a specific cell. Corrected one error in the pin matching routine.
Added a check in the pin matching routine to look for pins that
have been found to be no-connects after cleaning up the pin lists
of the children of that cell.