Merge pull request #1681 from drewhk/wip-3504-tone-down-remote-logging-drewhk

+rem #3504: Toned down error logging and made loglevel configurable
Merge pull request #1675 from akka/wip-finish-connect-retries-patriknw

=act #3525 Retry finishConnect after OP_CONNECT
=act, rem, clu #3521: make serialize-messages work with core modules
+act #3529 Add convenience helper for looking up an actor by identity

* ActorSelection.resolveOne
Merge pull request #1671 from akka/wip-3529-identify-sugar-patriknw

+act #3529 Add convenience helper for looking up an actor by identity
=act #3389 Improve SSL closing sequence

* Port of this fix in Spray by @jrudolph from this pull request https://github.com/spray/spray/pull/400
Merge pull request #1673 from akka/wip-3541-better-logging-of-camel-activation-failures-ban

=cam #3541 Log Camel endpoint activation/deactivation failures as error
Merge pull request #1668 from akka/wip-3539-clearly-separate-and-update-current-and-future-cluster-doc-ban

=doc #3539 Update the cluster spec
Merge pull request #1674 from drewhk/wip-3521-remoting-internal-msg-noserialize-drewhk

=act, rem, clu #3521: make serialize-messages work with core modules
Merge pull request #1679 from akka/wip-3389-fix-ssl-engine-shutdown-ban

=act #3389 Improve SSL closing sequence
=pro #3558 Add validate-pull-request task
=act fix reference.conf comment for event-handler-startup-timeout
=tes #3563: Mark internal Testkit messages as NoSerializationVerificationNeeded
Merge pull request #1693 from drewhk/wip-3563-testkit-internal-msg-serialization-drewhk

=tst #3563: Mark internal Testkit messages as NoSerializationVerificatio...
Merge pull request #1692 from akka/wip-3558-validate-pr-task-patriknw

=pro #3558 Add validate-pull-request task (forward port)
=act #3565 Add ClassTag in Props.apply(creator)

* Remove deprecated apply without ClassTag
Merge pull request #1697 from akka/wip-3565-props-apply-master-patriknw

=act #3565 Add ClassTag in Props.apply(creator) (forward port)
fix scripts/authors.pl

- used to omit commits which touched only one file
- used to omit commits which only inserted or deleted lines
=rem #3566 Fix failing RemoteNodeRestartDeathWatchSpec

* Subject actor in freshSystem was not started when the "shutdown"
  message was sent. Solved by retry.
Merge pull request #1704 from akka/wip-3566-RemoteNodeRestartDeathWatchSpec-patriknw

=rem #3566 Fix failing RemoteNodeRestartDeathWatchSpec