Fixes the way response headers are parsed when using the jQuery client. Enables the response headers to be properly viewed in the UI. Previous logic consistently returned an empty set of headers. Includes minor changes to allow the use of JS strict mode, at least for this function.

See http://tools.ietf.org/html/rfc6749#section-3.3 for details.

The callback url is now determined correctly if the swagger index.html file and
therefore the o2c.html is not in root directory of the host.

Also the popup opens more than one authorization-request-tab in firefox
(seems to append the on-click js method instead of replacing it)