message: Added Toolbar to tweet
diff: import React from 'react';
  import {NavigationContext} from 'navigation-react';
  -import {StyleSheet, Text, Image, ScrollView, View, TouchableHighlight} from 'react-native';
  +import {StyleSheet, Text, Image, Platform, ScrollView, View, ToolbarAndroid, TouchableHighlight} from 'react-native';
  import Tweets from './Tweets';
  export default ({tweet: {account: {id: accountId, name, username, logo},
  text, time, retweets, likes, replies}}) => (
  <NavigationContext>
  {({stateNavigator}) => (
  + <>
  + <ToolbarAndroid
  + navIcon={require('./arrow.png')}
  + title="Tweet"
  + style={styles.toolbar}
  + onIconClicked={() => {
  + stateNavigator.navigateBack(1)
  + }} />
  <ScrollView contentInsetAdjustmentBehavior="automatic" style={styles.view}>
  <View>
  <View style={styles.heading}>
  @@ -31,11 +39,15 @@ export default ({tweet: {account: {id: accountId, name, username, logo},
  </View>
  <Tweets tweets={replies} stateNavigator={stateNavigator} />
  </ScrollView>
  + </>
  )}
  </NavigationContext>
  );
  const styles = StyleSheet.create({
  + toolbar: {
  + height: Platform.OS === 'android' ? 50 : 0,
  + },
  view: {
  paddingLeft: 20,
  paddingRight: 20,
  