TransitionDirector replication feature specification

Discussion thread	Status
	Drafting as of Oct 25, 2016

ReplicaController API: Transition directors have a private read-only replicaController API.

Provide the replica controller to the director's initializer.

This API is not accessible to sub-classes.

Example pseudo-code:

TransitionDirector {
  private readonly var replicaController
  init(replicaController)

ReplicaControllerDelegate API: Transition directors can assign a replicaControllerDelegate.

Subclasses are expected to set a custom replica controller delegate using this API.

Example pseudo-code:

TransitionDirector {
  var replicaControllerDelegate
}