Flag Warn as Obsolete
Flag Warn as Obsolete and update all usages of Warn to move to using Warning
introduce LogMessage as a container for passing around Format + Args
F# API - extended tell operators for right associavity and actor paths, extended API for ActorSelection
Adding better support for logging when using serilog by providing a way to provide the message format and args into the serilog logger instead of pre formatting the message
change to serilog logger to unwrap the LogMessage correctly to get the format and arguments, and also make the ctor public so I could get it to work.
Change the way we match args to property tokens to more closely match Serilog when you pass in too few or too many arguments
Merge pull request #402 from stefansedich/dev

Better serilog support
Move current ActorCell field out of ActorCell to new class

The new class InternalCurrentActorCellKeeper make it possible to
update which context is used right now. This is needed for TestKit
to initially set TestActor as context when ImplicitSender is used.
TestActor is always implicit sender

Use NoImplicitSender to remove this behavior.
Merge pull request #388 from HCanber/testkit-implicit-sender

Makes TestActor implicit sender to TestKit

Mark the testclass with NoImplicitSender to remove TestActor from being implicit sender.
Merge pull request #394 from Horusiath/fsharp-api-selectors

[F# API] More idiomatic API and more ActorSelection methods
resolved mergeconflict with dev (/src/core/Akka/Actor/Futures.cs)
integrated testkit changes (implicit sender #388) into Akka.Cluster.Tests
resolved Collection modified while enumerating bug