request simply didn't work. Apache doesn't forward that information. So
instead, I'm now using a hacky work-around that looks at the proxy IP to
determine whether it was an http or https request.
Still need to fix unit tests for this.
* changed controller.Users and controller.Root constructor arguments to support this.
* Updated INSTALL document accordingly.
* Client now will prepend this new http_url variable to the logout link.
Dan Helfman