[fix] Server-side rendering

`AppRegistry.prerenderApplication` now returns a style element for use
in app shells.

Guard use of `window` in APIs and Event plugin.

Fix #107
Fix #108

docs/apis/AppRegistry.md

@@ -16,8 +16,11 @@ into `runApplication`. These should always be used as a pair.
 (web) static **prerenderApplication**(appKey:string, appParameters: object)
 
 Renders the given application to an HTML string. Use this for server-side
-rendering. Return object is of type `{ html: string; style: string; }`, where
-`html` the prerendered HTML, and `style` is the prerendered style sheet.
+rendering. Return object is of type `{ html: string; style: string;
+styleElement: ReactComponent }`. `html` is the prerendered HTML, `style` is the
+prerendered style sheet, and `styleElement` is a React Component. It's
+recommended that you use `styleElement` to render the style sheet in an app
+shell.
 
 static **registerConfig**(config: Array<AppConfig>)
 

docs/guides/rendering.md

@@ -33,7 +33,7 @@ React.renderToStaticMarkup(<div />)
 
 Rendering using the `AppRegistry`:
 
-```
+```js
 // App.js
 
 import React, { AppRegistry } from 'react-native'
@@ -64,12 +64,12 @@ rendering.
 
 import React from 'react-native'
 
-const AppShell = (html, style) => (
+const AppShell = (html, styleElement) => (
   <html>
     <head>
       <meta charSet="utf-8" />
       <meta content="initial-scale=1,width=device-width" name="viewport" />
-      {style}
+      {styleElement}
     </head>
     <body>
       <div id="react-app" dangerouslySetInnerHTML={{ __html: html }} />
@@ -90,8 +90,8 @@ import AppShell from './AppShell'
 AppRegistry.registerComponent('App', () => App)
 
 // prerenders the app
-const { html, style } = AppRegistry.prerenderApplication('App', { initialProps })
+const { html, style, styleElement } = AppRegistry.prerenderApplication('App', { initialProps })
 
 // renders the full-page markup
-const renderedApplicationHTML = React.renderToString(<AppShell html={html} style={style} />)
+const renderedApplicationHTML = React.renderToStaticMarkup(<AppShell html={html} styleElement={styleElement} />)
 ```