title: React-navigation 'Home' should declare a screen
body: <p>I'm trying to get a handle on react-navigation by making a dead simple app; I just want two screens with buttons you can click on to go between them.  Here's my code:</p>
  
  <p>App.js:</p>
  
  <pre><code>import React from 'react';
  import {
      Text,
      View,
      Button
  } from 'react-native';
  
  import {
      StackNavigator,
  } from 'react-navigation';
  
  import OtherPage from './OtherPage';
  
  const Home = ({navigation}) =&gt; (
      &lt;View&gt;
          &lt;Text style={styles.title}&gt;Welcome&lt;/Text&gt;
          &lt;Button title="Other Page" onPress={() =&gt; {
              navigation.navigate('OtherPage')
          }}&gt;&lt;/Button&gt;
      &lt;/View&gt;
  );
  
  const Nav = StackNavigator(
      {
          OtherPage: { screen: OtherPage},
          Index: {
              screen: Home
          }
      },
      {
          initialRouteName: 'Index',
      }
  );
  
  export default () =&gt; &lt;Nav /&gt;;
  </code></pre>
  
  <p>OtherPage.js:</p>
  
  <pre><code>import React from 'react';
  import {
      Text,
      View,
      Button
  } from 'react-native';
  
  import { StackNavigator } from 'react-navigation';
  
  const OtherPage = ({navigation}) =&gt; (
      &lt;View&gt;
          &lt;Text&gt;Other Page&lt;/Text&gt;
          &lt;Button title="Go Home" onPress={() =&gt; {
              navigation.navigate('Home');
          }}&gt;&lt;/Button&gt;
      &lt;/View&gt;
  );
  
  import Home from './App';
  const Nav = StackNavigator(
      {
          OtherPage: { screen: OtherPage},
          Home: { screen: Home }, // THIS LINE CAUSES THE ERROR
      },
  );
  
  export default () =&gt; &lt;Nav /&gt;;
  </code></pre>
  
  <p>For some reason what I get back from <code>import Home from './App';</code> isn't a <code>screen</code> and so I get the error <code>Route 'Home' should declare a screen</code>.  It's definitely that line that's causing the problem, if I comment it out then the app loads and I can click the button on the home screen to go to the other page, but then of course I'm stuck there and can't go back.</p>
  
  <p>What's confusing me is that these files are essentially identical in how everything's declared, and for some reason <code>import OtherPage from './OtherPage';</code> is a valid <code>screen</code> but <code>import Home from './App';</code> isn't.</p>
  
  <p>Can anyone help me out?  What am I doing wrong?</p>