Merge pull request react-navigation#71 from asdullahsiddique/patch-1

Removed unused component importing

Author: brentvatne

docs/tab-based-navigation.md

@@ -136,7 +136,7 @@ class SettingsScreen extends React.Component {
 Usually tabs don't just display one screen — for example, on your Twitter feed, you can tap on a tweet and it brings you to a new screen within that tab with all of the replies. You can think of this as there being separate navigation stacks within each tab, and that's exactly how we will model it in React Navigation.
 
 ```js
-import { TabNavigator, TabBarBottom, StackNavigator } from 'react-navigation';
+import { TabNavigator, StackNavigator } from 'react-navigation';
 
 class DetailsScreen extends React.Component {
   render() {