YARN-1636. Augmented Application-history server's web-services to also expose new APIs for retrieving and storing timeline information. Contributed by Zhijie Shen.
svn merge --ignore-ancestry -c 1564829 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1564830 13f79535-47bb-0310-9956-ffa450edef68