Simplify ReactRenderer API when referencing default modules

samples/react/ReactGrid/Controllers/HomeController.cs

@@ -17,7 +17,6 @@ namespace ReactExample.Controllers
         {
             ViewData["ReactOutput"] = await ReactRenderer.RenderToString(this.nodeServices,
                 moduleName: "ReactApp/components/ReactApp.jsx",
-                exportName: "ReactApp",
                 baseUrl: Request.Path
             );
             return View();

samples/react/ReactGrid/ReactApp/boot-client.jsx

@@ -1,7 +1,7 @@
 import React from 'react';
 import ReactDOM from 'react-dom';
 import createBrowserHistory from 'history/lib/createBrowserHistory';
-import { ReactApp } from './components/ReactApp.jsx';
+import ReactApp from './components/ReactApp.jsx';
 
 // In the browser, we render into a DOM node and hook up to the browser's history APIs
 var history = createBrowserHistory();

samples/react/ReactGrid/ReactApp/components/ReactApp.jsx

@@ -2,7 +2,7 @@ import React from 'react';
 import { Router, Route } from 'react-router';
 import { PeopleGrid } from './PeopleGrid.jsx';
 
-export class ReactApp extends React.Component {
+export default class ReactApp extends React.Component {
     render() {
         return (
             <Router history={this.props.history}>