* Add client side token.

* Fix ci.

* Fix most codes of token auth at both sides.

* Add settings in config files.

* Make auth interceptor doesn't throw expcetion.

* Update AuthenticationSimpleChecker.java

* Update AuthenticationActivator.java

* Revert "Update AuthenticationActivator.java"

This reverts commit 0935f18fd6802ab84c12e0609c21ef753ff51be3.

* Merge branch 'feature/token-auth' of https://github.com/apache/incubator-skywalking into feature/token-auth

# Conflicts:
#	apm-collector/apm-collector-agent/agent-grpc/agent-grpc-provider/src/main/java/org/apache/skywalking/apm/collector/agent/grpc/provider/AuthenticationSimpleChecker.java

* Fix Auhentication token works incorrect (#1001)

* Fix Auhentication token works incorrect

* Change way to build GRPC Channel

* Response an empty header when auth fails.

Fix IPMC checks for releasing.

* Support direct server setting in agent.

* Fix format.

* Add direct_servers check (#981)

* Finish the prototype of TLS of gRPC between agent and server.

* Fix for rat check.

* Update GRPCChannelManager.java

* Update AgentModuleGRPCProvider.java

* Upgrade netty version (#971)

* Make sure end user can't start gRPC server with and without SSL in the same port.

2. Setting the src span type when agent register service name.
3. Revert the topology build logic.

Fixing javadoc. And try to trigger a ci fail in this commit, in order to make sure javadoc will be checked in further pull request.