Nested routes

Fixes #262

test/app/app/client.js

@@ -1,13 +1,11 @@
 import { init, prefetchRoutes } from '../../../runtime.js';
 import { Store } from 'svelte/store.js';
-import { routes } from './manifest/client.js';
-import App from './App.html';
+import { manifest } from './manifest/client.js';
 
 window.init = () => {
 	return init({
 		target: document.querySelector('#sapper'),
-		App,
-		routes,
+		manifest,
 		store: data => new Store(data)
 	});
 };