=pro use sbt 0.13.2
=tes Remove some old (dead) test/sample code
=pro Update genjavadoc version to 0.7
=pro Remove unused atmos project in build
+con #3972 Make Distributedpubsubmediator support consumer group

1. allow Topic have children topics, which are the groups
2. when publish with sendOneMessageToEachGroup flag, it will send to one
actor each group
Merge pull request #15009 from 2m/use-sbt-13-2-2m

=pro use sbt 0.13.2
Merge pull request #15012 from akka/wip-3969-update-gen-javadoc-master-ban

=pro Update genjavadoc version to 0.7
Merge pull request #15010 from akka/wip-old-cleanup-patriknw

=tes Remove some old (dead) test/sample code
Merge pull request #15013 from akka/wip-remove-atmos-in-build-patriknw

=pro Remove unused atmos project in build
Merge pull request #2115 from cowboy129/master

+con #3972 Make Distributedpubsubmediator support consumer group
Fixed a typo
Merge pull request #15020 from sslavic/patch-1

=doc fixed a typo in remoting docs