Version 0.13.4

Adding CORS request and response headers: Access-Control-Allow-Credentials, Access-Control-Allow-Headers, Access-Control-Allow-Methods, Access-Control-Allow-Origin, Access-Control-Expose-Headers, Access-Control-Max-Age, Origin, Access-Control-Request-Headers, and Access-Control-Request-Method.

Add a brief tutorial on handling CORS pre-flight requests.

Fix a big in handling POST forms with parameters passed in with the application/x-www-form-urlencoded content type. These are now correctly processed.