message: Passed selected prop to TabBarItem
diff: import React from 'react';
  import { requireNativeComponent, StyleSheet } from 'react-native';
  -class TabBar extends React.Component {
  +class TabBar extends React.Component<any, any> {
  constructor(props) {
  super(props);
  this.state = {selectedTab: 0};
  }
  render() {
  + var {children, ...props} = this.props;
  return (
  <NVTabBar
  - {...this.props}
  + {...props}
  onTabSelected={({nativeEvent}) => {
  this.setState({selectedTab: nativeEvent.tab})
  }}
  - style={styles.tabBar} />
  + style={styles.tabBar}>
  + {React.Children.map(children, (child: any, index) => {
  + var childProps = {...child.props, selected: index === this.state.selectedTab};
  + return React.cloneElement(child, childProps);
  + })}
  + </NVTabBar>
  );
  }
  }
  