Introduce "strom-yarn shutdown" (issue #10)

This pull request introduce "shutdown" capability to storm-yarn. 
     storm-yarn shutdown --appId &lt;appID>

The shutdown command will stop Storm processes (Nimbus, Supervisors, UI etc), and also stop Storm Master server. All resources will be released as well.

I also made sure that Storm Master has a storm.yaml with correct host name for Storm Nimbus host. This will enable "storm jar" to simply use the a storm.yaml retrieved from "storm-yarn getStormConfig".