$.ajax delete request not sending data parameters in capybara-webkit
Apparently QtWebKit does not support an entity body with DELETE requests.
https://github.com/thoughtbot/capybara-webkit/issues/427#issuecomment-12200262
A capybara-webkit developer recommended this work-around: "[Send] a POST request with a parameter identifying the request as a DELETE. This mechanism is used by Rails to work around similar issues across browsers."