=doc Update Sphinx installation instructions
=doc,osg Effort to get OSGi integration tests running again

* Update protobuf dependency so mvn clean install runs again
* Bump OSGi version range in AkkaBuild to include current 2.3 for generated manifests
* Update path in dev documentation to correct TexBasic folder
Merge pull request #1817 from sandermak/osgi-sample-improvements

=doc,osg Effort to get OSGi integration tests running again
Merge pull request #1816 from akka/wip-sphinx-patriknw

=doc Update Sphinx installation instructions
=pro #3448 Upgrade to sbt 0.13.0
=all #3448 Newer Scalariform running on more files
Merge pull request #1791 from akka/wip-3448-update-to-sbt-0.13-ban

=pro #3448 Upgrade to sbt 0.13.0
+doc #3656 correcting the TypedActor documentation
=act #3601 Harden test for log dead letters
=act,rem #3073 Make ActorSelection faster
Merge pull request #1813 from akka/wip-3073-faster-actorselection-patriknw

=act,rem #3073 Make ActorSelection faster
Merge pull request #1820 from akka/wip-3601-ActorSystemSpec-patriknw

=act #3601 Harden test for log dead letters
+act #3579 Direct ActorSelection for missing actor to deadLetters
=pro Upgrade to sbt 0.13.1-RC2 to avoid too many open files.
Merge pull request #1826 from akka/wip-upgrade-to-sbt-0.13.1-RC2-ban

=pro Upgrade to sbt 0.13.1-RC2 to avoid too many open files.
=rem #3706 Avoid loss of floating point precision in PhiAccrualFailureDetector
=act Log random seed in case of SupervisorHierarchySpec failure

* It will never be deterministic, but with reproducble random sequence we
  might have a better chance to repeat run the test to reproduce failure.
Merge pull request #1832 from robdavid/wip-3706-avoid-loss-of-floating-point-precision-in-phiaccrualfailuredetector

=rem #3706 Avoid loss of floating point precision in PhiAccrualFailureDe...
=zer #3512 Harden zeromq ConcurrentSocketActorSpec

* 3 sec timeout waiting for terminated increased to 5 sec,
  ConcurrentSocketActor postStop (poller.unregister or socket.close)
  might perhaps take a while
* message from previous test step interleaved with next step, use
  separate endpoints for each step
!per #3707 Channel enhancements

- Persistent channel
- ConfirmablePersistent message type delivered by channel
- Sender resolution performance improvements
   * unstash() instead of unstashAll()

These enhancements required the following changes

- Unified implementation of processor stash and user stash
- Persistence message plugin API separated from implementation
- Physical deletion of messages