YARN-825. Fixed javadoc and annotations for yarn-common module. Contributed by Vinod Kumar Vavilapalli.
svn merge --ignore-ancestry -c 1493634 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1493635 13f79535-47bb-0310-9956-ffa450edef68
YARN-826. Moved Clock and SystemClock into yarn.util package. Contributed by Zhijie Shen.
svn merge --ignore-ancestry -c 1493639 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1493640 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9649. Promoted YARN service life-cycle libraries into Hadoop Common for usage across all Hadoop projects. Contributed by Zhijie Shen.
svn merge --ignore-ancestry -c 1493650 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1493651 13f79535-47bb-0310-9956-ffa450edef68
YARN-833. Moved Graph and VisualizeStateMachine into yarn.state package. Contributed by Zhijie Shen.
svn merge --ignore-ancestry -c 1493654 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1493655 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-2' into branch-2-gd