#423

2. make stream module as a collector define module, contains grpc remote service for call remote workers
3. worker framework is ok
4. Collector start ok

2. Add context help for every module to find another module’s context.

#266

1. Remove the “apm-trace” module, isolate the trace structure between agent and collector for considering performance.
2. Change the head name.
3. Provide potienal mechanism for ignore trace with certain suffix.

2.Release the prototype of ‘TraceSegment’.