message: Added TitleBarIOS usage demo to zoom sample.
diff: import React from 'react';
  import {StyleSheet, ScrollView, Text, View, Platform, TouchableHighlight} from 'react-native';
  import {NavigationContext} from 'navigation-react';
  -import {NavigationBarIOS, RightBarIOS, BarButtonIOS, SharedElementAndroid} from 'navigation-react-native';
  +import {NavigationBarIOS, RightBarIOS, BarButtonIOS, TitleBarIOS, SharedElementAndroid} from 'navigation-react-native';
  export default ({colors, color}) => (
  <NavigationContext.Consumer>
  {({stateNavigator}) => (
  <ScrollView contentInsetAdjustmentBehavior="automatic">
  <NavigationBarIOS title="Color">
  + <TitleBarIOS style={styles.titleBar}>
  + <Text style={styles.titleBarText}>Color</Text>
  + <View style={{backgroundColor: color, width: 28, height: 28}}/>
  + </TitleBarIOS>
  <RightBarIOS>
  <BarButtonIOS systemItem="cancel" onPress={() => {
  stateNavigator.navigateBack(1);
  @@ -49,6 +53,15 @@ export default ({colors, color}) => (
  );
  const styles = StyleSheet.create({
  + titleBar: {
  + flexDirection: 'row',
  + justifyContent: 'center',
  + alignItems: 'center'
  + },
  + titleBarText: {
  + marginRight: 4,
  + fontSize: 16
  + },
  back: {
  fontSize: 20,
  color: '#000',
  