allow overriding default response for failed auth
Add code required to subclass Api in the Response Formats example
Use 'super()' instead of 'restful.Api.', as per convention
Add crossdomain decorator from http://flask.pocoo.org/snippets/56/.

This adds support for CORS in flask-RESTful.
add CORS tests
remove basestring reference
fix test
Added support for using Blueprints instead of app instances.  Tests
incomplete.
Fixed/added tests, added documentation.
Removing errant print statement...
Merge pull request #125 from antonioherraizs/master

Add code required to subclass Api in the Response Formats example
add authors target to Makefile and generate AUTHORS.md
Potential fixes for error handling issues.
fields.Url() should return an external URL
-Added tests to validate error routing.
-Fixed issue with error routing found with tests.
Alternative prefix handling behavior for blueprint integration.
Removed commented code blocks.
Update fields.py
Update test_fields.py
add external option to Url field