Update AbstractNodeQueue.java

Avoid spinning on head when a peek/poll observes a null next but the queue is not empty.
Update AbstractNodeQueue.java

language language....
+act - #15501 - Adding support for a Non-blocking, bounded, MPMC mailbox called 'NonBlockingBoundedMailbox'
Fix isEmpty() and count()

isEmpty() need not rely on peek(which is intended for consumer use) and instead compare head to tail.
count() should stop counting at max int to avoid wrap.
Fixe documentation to state consumer only access is allowed to poll/peek/peekNode/pollNode
Doc stars err
Forgotten bracket
=tes Increase coroner timeout for some tests
=doc #15638 clarify message ordering rule

add a missing reference to the fact that it only applies to messages sent directly
=15648 ker Use wildcard in microkernel classpath

* scala-library.jar had changed name to scala-library-2.10.4.jar
* use wildcard to avoid same problem when scala-library version is changed
* the wilcard will only include jar files in the lib directory, and not the
  lib/akka directory, see 'Understanding class path wildcards'
  http://docs.oracle.com/javase/6/docs/technotes/tools/windows/classpath.html

(cherry picked from commit 996de05b44531bda517ef8ee274a34ad76e9716f)
Merge pull request #15660 from akka/wip-15648-classpath-master-patriknw

=15648 ker Use wildcard in microkernel classpath (for validation)
Improve docs for AtLeastOnceDelivery recovery

The Eventsourced migration guide currently suggested AtLeastOnceDelivery is
less useful than it actually is :)
Merge pull request #15662 from raboof/AtLeastOnceDeliveryDocs

Improve docs for AtLeastOnceDelivery recovery
=pro #15664 Use scala version in dist files
Merge pull request #15596 from nitsanw/master

Update AbstractNodeQueue.java to avoid redundant reads of head in peekNode
!act #15626 expose DatagramChannel creation in DatagramChannelCreator

* move channel creation logic to a separate trait
* new Java API: AbstractSocketOption
!con #15496 Remember entries in cluster sharding

- Move all entry related logic out of the ShardRegion and into a
  new dedicated child `Shard` actor.
- Shard actor persists entry started and passivated messages.
- Non passivated entries get restarted on termination.
- Shard Coordinator restarts shards on other regions upon region failure or handoff
- Ensures shard rebalance restarts shards.
- Shard buffers messages after an EntryStarted is received until state persisted
- Shard buffers messages (still) after a Passivate is received until state persisted
- Shard will retry persisting state until success
- Shard will restart entries automatically (after a backoff) if not passivated and remembering entries
- Added Entry path change to the migration docs
Merge pull request #15627 from 2m/udp-proto-family

!act #15626 expose DatagramChannel creation in SocketOption
Security: use https to fetch repo artifacts. See http://blog.ontoillogical.com/blog/2014/07/28/how-to-take-over-any-java-developer/
Merge pull request #15676 from benmccann/https-repos

Security: use https to fetch repo artifacts in examples