=clu #3941 SurviveNetworkInstability ignore leftover pings
+act,mul #3948 add MultiNodeSpec.startNewSsytem() and system.abort()

abort() currently only changes that remote-deployed child actors are not
waited for during termination (because that would not change anything);
it is still a different operation than shutdown() since it changes what
you are guaranteed to observe after termination.

testConductor.shutdown(..., abort = true) uses this mode of termination.

improve MultiNodeSpec to allow injection of deployment configuration
into arbitrary actor systems

include number of received elements in the timeout failure message for
TestKit.receiveN
+act #3949 add LoggingReceive.withLabel

def someState = LoggingReceive.withLabel("some state") {
  case msg => ...
}
=act,rem #3930 part 1: remote daemon watches parents

also stop child actors which are replaced in VirtualPathContainers
=rem #3930 part 2: track UID of associated systems

for proper clean-up of the old association (including the writer) when
the restarted system connects before the old association has been torn
down
Merge pull request #2090 from akka/wip-remoting-multi-fix-∂π

Wip remoting multi fix ∂π (broken commits apart properly)