Let the ActorSystem find its configuration outside of the bundle, in the OSGi etc directory, following this order:
    etc/bundle-BUNDLE_SYMBOLIC_NAME.conf
    etc/bundle-BUNDLE_ID.conf
    etc/akka.conf
    akka-actor classpath config (using the original  OsgiActorSystemFactory.actorSystemConfig method.)

Configurations fallback from the most to the less specific one.

For the moment, as I haven't found test on ActorSystem Configuration in OSGi, I did not add test for this feature.
    	modified:   akka-osgi/src/main/scala/akka/osgi/OsgiActorSystemFactory.scala
 patriknw comments commited

        * .conf, .properties, .json configuration files
        * string interpolation
        * take place of the legacy actorSystemConfig
rkuhn comments applied: no more extension  
Publish clean state when joining (PublishStart), see #2871

* The failure in JoinTwoClustersSpec was due to missing publishing
  of cluster events when clearing current state when joining
* This fix is in the right direction, but joining clusters like this
  will need some design thought, creating ticket 2873 for that
create akka-io subproject, see #2884
Adjust protocol pattern in LogRoleReplace for new remoting
Merge pull request #1003 from akka/wip-protocol-pattern-LogRoleReplace-patriknw

Adjust protocol pattern in LogRoleReplace for new remoting
Merge pull request #984 from Crossing-Tech/master

akka-osgi provides configurations files in the etc directory (no need to repackage the bundle for configuration modification)
Merge pull request #1000 from akka/wip-2871-publish-on-clearState-patriknw

Publish clean state when joining (PublishStart), see #2871
Confirmation of throttle mode change, see #2877

* added some missing copyright headers
* Use ask inside ThrottlerTransportAdapter
* Change signature of managementCommand
Merge pull request #1007 from akka/wip-2877-propagate-statusPromise-throttler-patriknw

Propagate statusPromise down to the actual change in throttler, see #2877
Merge remote-tracking branch 'akkaMaster/master'