Add @xcaspar in the contributors list.

Fix witness class fail, because of different class loaders.

Fix the wrong key of poolMap

* 'master' of https://github.com/wu-sheng/sky-walking:
  update docker image version
  Update the http port of collector server
  Provide new data protocol for segment messages.
  chore(collector): add a check for process id in startup script

chore(collector): add a check for process id in startup script

update docker image version

Update the http port of collector server

Provide new data protocol for segment messages.

This reverts commit 323468f0.

This reverts commit 5b853ec3.

This reverts commit 19f2a561.

This reverts commit 323468f0.

This reverts commit 04041ebd.

* add feign default http plugin
add test case for feign default http interceptor

* move feign and okhttp plugins to the parent moudle

Remove out-of-date readme file.

add okhttp plugin(provide synchronous http calls )

 Support leaf span

Remove "financial support", as I had already left OneAPM, and no financial relationship with OneAPM.

# Conflicts:
#	apm-sniffer/apm-agent-core/src/main/java/org/skywalking/apm/agent/core/conf/Config.java
#	apm-sniffer/apm-agent/pom.xml
#	apm-sniffer/apm-sdk-plugin/pom.xml

add test case for okhttp interceptor