Update spark_ec2.py to use new spark-ec2 scripts
Fix swap variable name
Add option to start ganglia. Also enable Hadoop ports even if cluster type is
not mesos
Add an option to use the old scripts
Turn on ganglia by default
Merge pull request #421 from shivaram/spark-ec2-change

Switch spark_ec2.py to use the new spark-ec2 scripts.
Change EC2 script to use 0.6 AMIs by default, for now
Clean up EC2 script options a bit
Renamed "splits" to "partitions"
Rename "jobs" to "applications" in the standalone cluster