Merge pull request #2 from Ooblioob/master

Add support for multiple environments with differing version
Adds settings exportation functionality
Fixes vagrant, updates documentation

- README gives a more accurate picture of how deployments work
- Vagrant deploys can be done from outside the vagrant home
- Updates functionality for migrating, version controlling settings
Removed settings, better check for wp-cli

- Removed some settings that might be environment specific
- now checks for wp-cli both in the settings and on the server (was only in
  settings.)
- Added a possible 'no-deploy' key to a server to force fab deploy to fail on servers
  you want to exclude
Role based execution model

- git fab build a role and watch er go! Also override the WP version by passing a
  parameter
Updated config.yaml for role-based workflow