Work with Karsten on TorPerf Experiments

This ticket is to catalog my portion of the work with karsten on #2769 (closed). I plan to help with a few experiments:

• Determine new guard cutoff: 2pts
• Determine optimal CircWindow: 6pts
• Throttle clients network-wide: 4pts
• Disable EWMA: 1pt
• Extra luck point: 1pt