Overhaul README with different deployment scenarios
Overhaul README with different deployment scenarios

Particularly:

- How to deploy the "prod" templates over cmdline
- How to deploy latest master
- How to deploy local changes

Also document the source tree a bit, and talk about how to create a new
base AMI.

Signed-off-by: Ken Simon <d689d7adec1f250ae6789ab10f904ed792f264cd@gmail.com>

heptio/aws-quickstart,heptio/aws-quickstart