=act #3557 Improved semantics for BoundedBlockingQueue

- Blocking methods lock interruptibly
- drainTo can no longer drain to the backing
- drainTo/clear now calls signalAll instead of signal

Also made some other changes to make the code nicer (I hope!).
=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 #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
=clu #3442 Optimize the vector clock comparison
Merge pull request #1705 from akka/wip-3442-optimize-gossip-comparison-ban

=clu #3442 Optimize the vector clock comparison
!clu #2320 Convert the seen table into something more efficient
Merge pull request #1706 from akka/wip-2320-optimize-the-seen-table-ban

!clu #2320 Convert the seen table into something more efficient
+act #3592 Read stash-capacity from mailbox config
+con #3551 Buffer messages in cluster client

* Stash when establishing connection to receptionist
=act #3593 Turn of serialize-messages and make receive polymorphic