EC2 Support through Ansible.

[robertmaynard]

Extend the cdep format to support ansible definitions for a machine. Currently all machines are implicitly
expected to be online and running when cfarm commands are invoked. Now we need to extend the syntax to support remote instance based machines.

Questions that need to be resolved:

1. Does setting up an instance based machine create an AMI?
2. Do we terminate instances between build/test invokes or let them run? Is this a config file option?
3. How can cfarm easily add in the ability to update the AMI?

Docs:
http://docs.ansible.com/guide_aws.html
https://aws.amazon.com/articles/3998