=act #3602 report `Connected` only when connection attempt was successful

Before this change, a client connection was always instantly reported as
`Connected`, even if the endpoint would never respond at all.

The reason is a weird behavior of OP_CONNECT and SocketChannel in the
JDK (observed in Linux):
 - a channel is always connectable before the connection is attempted
   (`channel.connect`). Selecting for OP_CONNECT before the `connect`
   call will instantly report connectable
 - even worse: after OP_CONNECT was reported true, also `finishConnect`
   will always return true, even if the connection wasn't yet established.
   That's probably the case because `finishConnect` is internally implemented
   depending on previous epoll results (on Linux).
!act,rem,clu #3549 Simplify and enhance routers

* Separate routing logic, to be usable stand alone, e.g. in actors
* Simplify RouterConfig, only a factory
* Move reading of config from Deployer to the RouterConfig
* Distiction between Pool and Group router types
* Remove usage of actorFor, use ActorSelection
* Management messages to add and remove routees
* Simplify the internals of RoutedActorCell & co
* Move resize specific code to separate RoutedActorCell subclass
* Change resizer api to only return capacity change
* Resizer only allowed together with Pool
* Re-implement all routers, and keep old api during deprecation phase
* Replace ClusterRouterConfig, deprecation
* Rewrite documentation
* Migration guide
* Also includes related ticket:
  +act #3087 Create nicer Props factories for RouterConfig
Merge pull request #1746 from akka/wip-3549-shiny-routers-patriknw

!act,rem,clu #3549 Simplify and enhance routers
Merge pull request #1729 from jrudolph/wip-3602-fix-connected

=act #3602 report `Connected` only when connection attempt was successful
=rem #3666: Explicitly log invalid outbound addresses
(cherry picked from commit e8bbcf8)
=rem : Update comment in logging section of remoting configuration
(cherry picked from commit 0510163)
Merge pull request #1775 from drewhk/wip-logging-config-comment-fwdport-drewhk

=rem : Update comment in logging section of remoting configuration (forward port)
Merge pull request #1774 from drewhk/wip-3666-log-missing-port-fwdport-drewhk

=rem #3666: Explicitly log invalid outbound addresses (forward port)