* feature/3.0:
  fix coverall maven plugin issue
  fix coveralls issue

# Conflicts:
#	pom.xml

Support ci and coverage.

Fix confirm.

Try to fix coveralls issue. Give it a try.

merge Feature/3.0

* feature/3.0:
  no message
  Add generated source codes to src/main/java, try to avoid coveralls bug.

# Conflicts:
#	skywalking-collector/skywalking-collector-cluster/src/main/java/com/a/eye/skywalking/collector/actor/AbstractWorker.java

* feature/3.0:
  Test ci of protobuf
  update the comment to improve the comment readable
  update the comment to improve the comment readable
  Alter dependency.version
  Fix compile issue.
  Fix compile issue.
  Rewrite  plugins by using  new API
  Modify the redis plugin using the new API
  Modify the motan plugin using the new API
  Modify the Tomcat plugin using the new API
  Modify the Dubbo plugin using the new API

2. created workerref class use for cover akka actorref class

Rewrite plugin using new API

# Conflicts:
#	skywalking-collector/skywalking-collector-actor/src/main/java/com/a/eye/skywalking/collector/actor/AbstractWorker.java

* feature/3.0:
  Update grpc to 1.1.2

* feature/3.0:
  Alter ContextCarrier, add applicationCode and peerHost
  remove a test main.
  Fix compile issue.
  Add a new field, applicationCode,  in TraceSegment.
  Add a log field.
  Fix ‘tags.get’ cause ClassCastException, because after akka-message/serialize, all tags values are type of String.class.
  Fix serialize bugs.
  Add ISerializable interface, and implement this interface in ‘TraceSegment’, ‘TraceSegmentRef’, ‘Span’, ‘LogData’
  Add the trace proto file.
  Fix some compile issues. Add protobuf dependency, and protoc-grpc-plugin.
  Fix log-toolkits(log4j, log4j2, logback) compile issue.
  Fix opentracing-toolkit activation compile issue, and useless codes.

# Conflicts:
#	pom.xml

Give a new demo AbstractWorkerProviderTestCase.