Added a --region option to the REPL.
Removed an unused helper from the apis.rake task file.
Added a api:versions rake task that displays supported services and api versions.
Reworked structure of API rake tasks.

Removed the `rake apis` task. You can now translate APIs
for all services by running:

    rake api:translate

If you want to translate all APIs for a single service:

    rake api:translate:dynamodb

Lastly, you can translate a single API by version:

    rake api:translate:dynamodb:2012-08-10
Added a rake task that updates the table of supported services in the README.
Updated the Route53 API to user integers for the :max_items inputs/outputs.
Updated API doc plugin to load API source from new location.
Added basic integration tests for RDS.
Added basic route53 integration tests.
Added basic integration tests for Redshift.