Akka scheduler-based runner

The runner is located in SubScriptActorRunner.scala file, with certain insignificant modifications that were needed to make it run. The name of the runner object is SSARunnerV1Scheduler, where V1 means version and Scheduler briefly describes version - I think this will be handy in future during various runners comparison. As for now, it works nicely with ping-pong example: http://pastebin.com/XqmVz4Yk