switch to single App component model (#157)

test/app/app/App.html

@@ -0,0 +1 @@
+<svelte:component this={Page} {...props}/>

test/app/app/client.js

@@ -1,9 +1,13 @@
 import { init, prefetchRoutes } from '../../../runtime.js';
 import { Store } from 'svelte/store.js';
 import { routes } from './manifest/client.js';
+import App from './App.html';
 
 window.init = () => {
-	return init(document.querySelector('#sapper'), routes, {
+	return init({
+		target: document.querySelector('#sapper'),
+		App,
+		routes,
 		store: data => new Store(data)
 	});
 };

test/app/app/server.js

@@ -5,6 +5,7 @@ import serve from 'serve-static';
 import sapper from '../../../dist/middleware.ts.js';
 import { Store } from 'svelte/store.js';
 import { routes } from './manifest/server.js';
+import App from './App.html'
 
 let pending;
 let ended;
@@ -86,6 +87,7 @@ const middlewares = [
 	},
 
 	sapper({
+		App,
 		routes,
 		store: () => {
 			return new Store({