Add tests for Router.AddRoutee
Add Router.RemoveRoutee & implicit casting ActorRef -> ActorRefRoutee

Simplify AddRoutee, that has the same logic copy-pasted.

Breaking change: Router.Send should not be public. This can never have been meant to be public and I can't see why anyone would actually use it from the outside. The public send-to-routees is Route(). The impact of this breaking change should be slim to nothing.
Clearer tests
Make InternalRef protected as it was accidentally made public.
Issues 292 & 403 : loggers moved to Akka.Logger.* . ensured NLogLogger has a public constructor
Merge pull request #443 from HCanber/testactorref

Make InternalRef protected as it was accidentally made public.
Merge pull request #440 from mmisztal1980/i403_292

Loggers moved to Akka.Logger.* namespace
NLogLogger has a public constructor
Merge pull request #441 from HCanber/router-439

Adds Router.RemoveRouter