* feature/collector:
  dag graph finish
  dag graph reached a crossroads
  no message
  add dag node search service use jetty servlet
  no message

Fix typo, and remove unnecessary lock in NoConcurrencyAceessObject. Refact FileWriter and SnifferConfigInitializer.

fix issue

# Conflicts:
#	skywalking-collector/skywalking-collector-commons/src/main/java/com/a/eye/skywalking/collector/commons/serializer/TraceSegmentSerializer.java

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.