Removed unused UpdatedRates message
Differentiate between REMOTE and LOCAL sync periods.
No need to tell local slave on coflow registration/unregistration. It’ll be done by Varys*Stream objects.
Removed unused code.
Updating coflow sizes locally without using iptables with several benefits:
 - Precise accounting.
 - Saves about 20 milliseconds by not having to create a ProcessBuilder
 - Coflows are registered on demand.
 - Coflows are (considered) unregistered after some period of inactivity. This gives periodic coflows to catch up.
Close Varys streams or streams that encapsulate Varys. We should be able to avoid this requirement soon though.
Updated local slave on Flow Start and Completion events.
Remove Slave communication from VarysClient, which only works with Master to register and unregister coflows.
Updated coflowId
Rate limit updates to master.
Waiting for replies cause errors when actual application has already finished. This should be fine because Akka guarantees ordered delivery between src-dst pairs.