MAPREDUCE-5184. Document compatibility for MapReduce applications in hadoop-2 vis-a-vis hadoop-1. Contributed by Zhijie Shen.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1493570 13f79535-47bb-0310-9956-ffa450edef68
YARN-829. Renamed RMTokenSelector to be RMDelegationTokenSelector. Contributed by Zhijie Shen.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1493577 13f79535-47bb-0310-9956-ffa450edef68