Fix bookmarklet on pages that have an older version of jQuery loaded (<1.5)

A problem manifests itself on the Microsoft TechNet pages (http://technet.microsoft.com/en-us/magazine/default.aspx).  The pages load an old version jQuery(1.2.6).  The particular ajax method used to send the POST request was introduced in jQuery 1.5.  In order to ensure that the proper method is available, load the latest jQuery regardless of what the current page has.
I also added a bit of cleanup to remove the script element after we have sent the ajax request, since it isn't necessary anymore.