Updated ralph submodule requires different alias command.
Issue barrier at end of switch_rtable_updates
change to my floodlight fork
Updated ralph dependency to permit returning lists.
Reverted Daniel's change, which included barriers, because there's
a bug with his floodlight implementation of barriers.
Added experimental setup to produce numbers for latency graph.
Repeatedly enters and removes a flow table entry for a particular
switch and measures how long each operation took.