title: react native this.props.navigation is undefined in main APP
body: <p>I'm trying to use "this.props.navigation" in my main react native App but it is undefined. In my others components included with TabNavigator and ScreenNavigator it work.</p>
  
  <p>My App.js </p>
  
  <pre><code>const MyTabView = TabNavigator(
    {     
      Projects: { screen: Projects },     
      Explorer: { screen: Explorer },
      Profil: { screen: Profil }, ... 
    }        
  );
  
  
  
  const StackView = StackNavigator(
    {
      global: {
        screen: MyTabView,
        headerMode: "none",
        header: null,
        navigationOptions: {
          header: null
        }
      },
  
      TermsOfUse: { screen: TermsOfUse },
      LegalNotice: { screen: LegalNotice },
      Options: { screen: Options }, ...       
    } 
  );
  
  export default class App extends React.PureComponent {
    constructor (props) {
      super(props); 
      console.log(this.props.navigation); // &lt;----------  UNDEFINED
    }
  
  
    render() {
      return (
        &lt;Provider store={store}&gt;
          &lt;PersistGate
            loading={&lt;ActivityIndicator /&gt;}
            persistor={persistor}&gt;
  
            &lt;View style={styles.fullScreen}&gt;
              &lt;StackView /&gt;
  
              &lt;Tutorial navigation={this.props.navigation} /&gt;  // &lt;----------  this.props.navigation  is  UNDEFINED
            &lt;/View&gt;
          &lt;/PersistGate&gt;
        &lt;/Provider&gt;
      );
    }
  }
  </code></pre>