Finish CollectorClient code. It is almost ready to send TraceSegement (s) to collector in batch/fail-switch mode.

Add test cases

Fix compile issue. Add new rest-service Object: SegmentsMessage.java. It uses Gson(JsonAdapter) as serialize/deserialize tool.

Remove collector dependency from agent-module. We will use HTTP-restful-service. Remove unnecessary dependencies/shades on collector and agent sides. Fix CI issue.

Add equals methods for DistributedTraceId and TraceSegmentRef. Avoid duplication in TraceSegment, based on LinkedList.contains().

1.Remove two useless ClusterConfig. 2.Adjust ClusterConfig.class and its mapping properties file,  rename to ’seed_nodes’ .

1.Move ‘application.conf’ to collector-commons module. 2.Remove the unnecessary contents in‘application.conf’. 3.Remove ISerializable interface(useless)

# Conflicts:
#	skywalking-collector/skywalking-collector-cluster/src/main/java/com/a/eye/skywalking/collector/actor/Context.java
#	skywalking-collector/skywalking-collector-worker/src/main/java/com/a/eye/skywalking/collector/worker/applicationref/ApplicationRefMain.java

refactor ClusterContext and LocalContext implements Lookup interface that let the user of context just use lookup or findprovider method.

* feature/3.0:
  compile error
  refactor the way how to create worker instance
  1. Remove the primary ref. Only use ref to the parent segment. 2. Adjust globalTracerIds
  refactor cluster module, modify the way use to tell cluster worker
  Add tags test case.
  Add new test case for 3 InvokeContextTest.
  Fix interceptor instance singleton bug, and add some test cases.
  Alter TraceSegement, Add a list of DistributedTraceId as field `relatedGlobalTraces`.
  Shade akka.* in collector-worker. Prevent akka se/deserializing failure.
  Rename ServiceStarter to ServiceManager. Finish the major codes of TraceSegmentProcessQueue and CollectorClientService.
  Sync a result pom
  add recevier moudle
  fix test case issue
  fix tomcat cannot works issue
  fix #103
  Add a new ability to ServiceStarter, about finding a started service instance.
  Fix a test case failure issue.
  Recover logging-api/logging-log4j2 modules. Adjust codes for new modules.

* feature/collector:
  compile error
  refactor the way how to create worker instance
  refactor cluster module, modify the way use to tell cluster worker
  add recevier moudle

# Conflicts:
#	skywalking-collector/pom.xml
#	skywalking-collector/skywalking-collector-cluster/pom.xml
#	skywalking-collector/skywalking-collector-cluster/src/main/java/com/a/eye/skywalking/collector/actor/AbstractMember.java
#	skywalking-collector/skywalking-collector-cluster/src/main/java/com/a/eye/skywalking/collector/actor/AbstractWorker.java
#	skywalking-collector/skywalking-collector-cluster/src/main/java/com/a/eye/skywalking/collector/actor/AbstractWorkerProvider.java
#	skywalking-collector/skywalking-collector-cluster/src/main/java/com/a/eye/skywalking/collector/actor/WorkerRef.java
#	skywalking-collector/skywalking-collector-cluster/src/main/java/com/a/eye/skywalking/collector/actor/WorkersCreator.java
#	skywalking-collector/skywalking-collector-cluster/src/main/java/com/a/eye/skywalking/collector/cluster/WorkersListener.java
#	skywalking-collector/skywalking-collector-worker/pom.xml
#	skywalking-collector/skywalking-collector-worker/src/main/java/com/a/eye/skywalking/collector/worker/CollectorBootStartUp.java

2. Adjust globalTracerIds

Update latest release version to 2.3

Finish the major codes of TraceSegmentProcessQueue and CollectorClientService.

fix tomcat cannot works issue

# Conflicts:
#	skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/CallableStatementTracing.java
#	skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/ConnectionTracing.java
#	skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/PreparedStatementTracing.java
#	skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/StatementTracing.java