Integrated new topology code and updated unit tests to a passing state. I'd be...

Integrated new topology code and updated unit tests to a passing state. I'd be more comfortable adding more unit tests to the topology. Also made some changes to the link discovery manager's latency subsystem. We start with a baseline latency based on the switch's features reply turnaround time. This should be relatively quick -- just like an echo. Next step for latency is to keep a rolling list of past latencies for more defined topology updates based on latency updates. We don't want to update latencies too frequently, since tiny changes (or outliers) shouldn't require a complete topology recomputation.