Fix bug JIRA-923
cut lines to less than 100
fix format error
Enable stopping and starting a spot cluster
Merge pull request #160 from xiajunluan/JIRA-923

Fix bug JIRA-923

Fix column sort issue in UI for JIRA-923.
https://spark-project.atlassian.net/browse/SPARK-923

Conflicts:
	core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala
	core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala
Merge pull request #153 from ankurdave/stop-spot-cluster

Enable stopping and starting a spot cluster

Clusters launched using `--spot-price` contain an on-demand master and spot slaves. Because EC2 does not support stopping spot instances, the spark-ec2 script previously could only destroy such clusters.

This pull request makes it possible to stop and restart a spot cluster.
* The `stop` command works as expected for a spot cluster: the master is stopped and the slaves are terminated.
* To start a stopped spot cluster, the user must invoke `launch --use-existing-master`. This launches fresh spot slaves but resumes the existing master.