fix url base on invite and broken getLanguages

main.go

@@ -596,7 +596,9 @@ func start(asDaemon, firstCall bool) {
 		app.debug.Println("Loading pprof")
 		pprof.Register(router)
 	}
-	router.GET("/lang/:page", app.GetLanguages)
+	for _, p := range routePrefixes {
+		router.GET(p+"/lang/:page", app.GetLanguages)
+	}
 	if !firstRun {
 		for _, p := range routePrefixes {
 			router.GET(p+"/", app.AdminPage)

views.go

@@ -166,7 +166,7 @@ func (app *appContext) InviteProxy(gc *gin.Context) {
 		email = ""
 	}
 	gcHTML(gc, http.StatusOK, "form-loader.html", gin.H{
-		"urlBase":           app.getURLBase,
+		"urlBase":           app.getURLBase(gc),
 		"cssClass":          app.cssClass,
 		"contactMessage":    app.config.Section("ui").Key("contact_message").String(),
 		"helpMessage":       app.config.Section("ui").Key("help_message").String(),