YARN-595. Refactor fair scheduler to use common Resources. Contributed by Sandy Ryza.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1475670 13f79535-47bb-0310-9956-ffa450edef68
YARN-289. Fair scheduler allows reservations that won't fit on node. Contributed by Sandy Ryza.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1475681 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-HDFS-4312-trunk-gd