[UNSTABLE] PipeTo pattern, PhiAccrualFailureDetector, ProtocolStateActor, specs

Added the following:

* `PipeTo` pattern support - automatically sends the result of a completed task directly to an Actor's mailbox
* Implemented the `PhiAccrualFailureDetector` and its specs - 3 of the specs aren't passing at the moment; not sure if it's related to a bug in my test harness (time series faker) or in the class itself.
* Implemented the `ProtocalStateActor` finite state machine - about to begin work on specs for it.