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.

Remoe health-report module. Because the HealthCollector is based on ConcurrentHashMap. This triggers a performance issue, when the TPS is very high.( > 500)

2.Release the prototype of ‘TraceSegment’.

Fix some resources leak. Format log. Set jdk level of common lib to 1.6 . Fix some incorrect pom.xml .

2. 增加SDK的数据的测试

2. 提交测试工程

2.提交基于httpClient 4.x的插件代码。暂未完成所有功能。完成4.3下的测试，4.2待测试。

2.在客户端API中provided依赖log4j2，客户端指定所需版本

2. 修改工程名字