Add API Gateway IntegrationResponse header support #70
This adds support for static and dynamic IntegrationResponse headers as specified here: http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-apitgateway-method-integration-integrationresponse.html
The PR includes a CORS example and documentation for parameters within the Integration Response section.
I dug into the tests a bit, but didn't see an easy way to insert coverage. I'd love any direction/suggestions for adding test coverage.