Render the file specified in the path

This supports navigating between links.  :)

go/tmpview/tmpview.go

	if os.Args[1] == "serve" {
		addr := os.Args[2]
		fileName := os.Args[3]
		mux := http.NewServeMux()
		mux.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
			lastVisit = time.Now()
			fileName := req.URL.Path[1:]
			data, err := ioutil.ReadFile(fileName)
			if err != nil {
				http.Error(w, "could not read file", http.StatusNotFound)