YARN-553. Replaced YarnClient.getNewApplication with YarnClient.createApplication which provides a directly usable ApplicationSubmissionContext to simplify the api. Contributed by Karthik Kambatla.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1494476 13f79535-47bb-0310-9956-ffa450edef68