Navigator is deprecated and has been removed from this package

报错：'Navigator is deprecated and has been removed from this package. It 
 can now be installed ' +   'and imported from `react-native-deprecated-
custom-components` instead of `react-native`. ' +   'Learn about alternative
 navigation solutions at http://facebook.github.io/react-native/docs/navigation.html'

这是因为版本升级到0.43以上的话，Navigator不能直接从react-native里面获取了，

解决方案：

npm install react-native-deprecated-custom-components
 --save

然后在引用的地方

import {Navigator}
 from react-native-deprecated-custom-components