Jrbl/feature/doc update

* Rename *.yaml -> \1.yml
 * It can be either way (ansible doesn't care) but it should be only one way, and the preponderance of existing configuration used .yml.
 * Update to README to reflect changed filenames.
* Make AWS region selectable on CLI
 * Make it convenient (albeit, mandatory) to set AWS region on the command line when calling ansible-playbook for cloudformation
* README updates
 * Wrap to 80 columns
 * improved markdown conformance and plaintext readability
 * note about setting PYTHONPATH inside squeaky clean virtualenvs
 * note about using WikiWords as your cloudformation stack names
 * note about how sometimes ansible says 'ok' when cloudformation says something broke