v53

• Use EBS disks for ephemeral disk (/var/vcap/data) instead of instance storage
  • Very convenient when shutting down and starting up large number of machines directly in AWS
  • Can opt-in to use instance storage via ephemeral_disk.use_instance_storage=true
• Allow encryption of ephemeral disks via ephemeral_disk.encrypted=true property
• Allow use of new volume types: st1 and sc1 for ephemeral and persistent disks
• Allow mixing of security group names and IDs and be very explicit when exactly one security group cannot be found