urlutils: MS Office redirection workaround

• When a URL pointing e.g. to some restricted content is followed from a MS Office document, MS Office tries to be smart and already prefetch the content, and somehow passes the result to the browser. This might lead to lost session e.g. with SSO. A workaround is here implemented that provides MS Office with a simple HTML page and a 200 OK result, instead of the required redirection. The browser will then correctly follow the redirection. See http://support.microsoft.com/kb/899927.