Auctions can be held over http

This is a rebase of ~15 WIP commits.  This is necessary to make rebasing on top of master less insane:

- Add an http client and server
- support http communication mode
- support running the auction simulation *on diego*
- backfill a test for AddressLookupFromMap
- add logging to auction http client
- update readme
- support nats on diego
- switch to compare_to_percentile by default
- Rework how rep addresses are provided to the client
- support increasing number of reps/auctioneers
- backfill auctiontypes tests
- redo how remote auctioneer communication works in the simulation
- improve external auction communication
- add scenarios suite; pass maxConcurrent into the external auctioneers
- extract diego-cluster simulation out (now lives under https://github.com/pivotal-cf-experimental/diego-cluster-simulations)