Change Actor framework

[JiseongKim]

Currently, EAT using Actor(http://docs.paralleluniverse.co/quasar). But it doesn't provide external communication. So it has limitation to extends. To have load test, we can run it with multi-JVM.

But. expand to centralized-management(which can command to agents and monitor it) function, Actor model of EAT should have new Actor model(which can communicate with external nodes).

Currently I'm considering it with Akka Actor(http://akka.io).