VPC-local playbooks

Use these playbooks from a node in your VPC. This works better than using public IP addresses when using on-demand instances because public IP addresses can change across instance stops and restarts. It's not easy to automatically determine what they changed to after bringing them up so that the inventory can be updated.

This branch avoids the whole problem by running the playbooks from inside the VPC, which is faster and what the ansible guys recommend anyway. The downside are that this no longer works with the public IPs.