* [maven-release-plugin] prepare release v6.4.0

* [maven-release-plugin] prepare for next development iteration

* [maven-release-plugin] prepare release v6.3.0

* [maven-release-plugin] prepare for next development iteration

* [maven-release-plugin] prepare release v6.2.0

* [maven-release-plugin] prepare for next development iteration

* Move submodule plugin.

* Always auto-submodule

* [maven-release-plugin] prepare release v6.1.0

* [maven-release-plugin] prepare for next development iteration

* Change keys location.

* [maven-release-plugin] prepare release v6.0.0-GA

* [maven-release-plugin] prepare for next development iteration

* Lock oracle and resin plugins version.

* Move resin and oracle plugin to openskywalking

* Restore submodule active.

* Add another submodule active command.

* Remove the wrong test cases in release and fix some doc issues.

* [maven-release-plugin] prepare release v6.0.0-alpha

* [maven-release-plugin] prepare for next development iteration

* Fix some doc

* Fix mesh receiver doesn't update heartbeat.

* Fix bug of mesh heartbeat and rest receiver.

* Fix issue: opencensus is included in agent without shade. @tuohai666

* Buffer stream.

* Buffer file reader.

* Register start up.

* Service inventory register test success.

* Receiver, aggregate, server finished.

* Cluster module implementation finished.

#1009

* [maven-release-plugin] prepare release apm-5.0.0-alpha

* [maven-release-plugin] prepare for next development iteration

Fix assmbly for mvn clean install -Papache-release and update version to SNAPSHOT for SNAPSHOT release.

Make agent gRPC to be a collector module.
Make agent jetty to be a collector module.
Make agent stream to be a collector module.