title: Navigator.SceneConfigs can't find variable: Navigator
body: <p>I want to configure various scene animations with Navigator.SceneConfigs ("FloatFromRight" and "FloatFromLeft").</p>
  
  <p>Within the Scene - if I call the scene with a configured animation I receive the error message "Can't find variable: Navigator" (although I am of the opinion that I copied the code above from the React-Native examples).</p>
  
  <pre><code>_onPressBar1: function(){
      debugger;
      this.props.nav.push({
        id: 'Login',
        sceneConfig: Navigator.SceneConfigs.FloatFromLeft,
      });
    },
  </code></pre>
  
  <p>I created the following Navigator:</p>
  
  <pre><code>render: function() {
      return (
        &lt;Navigator
          style={styles.container}  
          renderScene ={this.renderScene}
          configureScene={(route) =&gt; {
            if (route.sceneConfig) {
              return route.sceneConfig;
            }
            return Navigator.SceneConfigs.FloatFromRight;
          }}
          initialRoute={{
            id: 'Login',
            index: 0,
          }} /&gt;
      );
    }
  </code></pre>
  
  <p>with the following renderScene:</p>
  
  <pre><code>renderScene: function(route, navigator){
      if ('Login' === route.id) {
      return (
        &lt;View style={{flex: 1}}&gt;
          &lt;TopBar nav={navigator} displBackIcon={false} /&gt;
          &lt;Login
            name={route.name}
            navigator={navigator} /&gt;
          &lt;BottomBar nav={navigator} currentPage={route.id} /&gt;
        &lt;/View&gt;
        );
      } else if ('Test' === route.id) {
        return (
          &lt;View style={{flex: 1}}&gt;
            &lt;TopBar nav={navigator} displBackIcon={false} /&gt;
            &lt;Test
                navigator={navigator} /&gt;
            &lt;BottomBar nav={navigator} currentPage={route.id} /&gt;
          &lt;/View&gt;
        );
      } 
    },
  </code></pre>