Ray on Spark API

For usage, see Deploying on Spark Standalone cluster.

ray.util.spark.setup_ray_cluster	Set up a ray cluster on the spark cluster by starting a ray head node in the spark application's driver side node.
ray.util.spark.shutdown_ray_cluster	Shut down the active ray cluster.
ray.util.spark.setup_global_ray_cluster	Set up a global mode cluster.