message: Added back right bar button on ios
diff: import React from 'react';
  import {StyleSheet, ScrollView, Text, View, Platform, TouchableHighlight} from 'react-native';
  import {NavigationContext} from 'navigation-react';
  +import {RightBarIOS, BarButtonIOS} from 'navigation-react-native';
  export default ({colors, color}) => (
  <NavigationContext.Consumer>
  {({stateNavigator}) => (
  <ScrollView contentInsetAdjustmentBehavior="automatic">
  + {Platform.OS == 'ios' && <RightBarIOS>
  + <BarButtonIOS systemItem="cancel" onPress={() => {
  + stateNavigator.navigateBack(1);
  + }} />
  + </RightBarIOS>}
  {Platform.OS !== 'ios' && <TouchableHighlight
  underlayColor="#fff"
  accessibilityRole="link"
  