React 16 and React Native 0.50 compatibility issues

[Nandez89]

Could you please make the component compatible with React 16/ React Native 50? Right now app in production crashes due to an "Unhandled JS Exception: undefined is not an object (evaluating 's.View.prop..., stack:'"

That is being caused by the use of View.propTypes in PasswordStregthChecker.js the way to fix this would be to check for the newer ViewPropTypes and default to the old one if its not there. Like so: ViewPropTypes || View.propTypes

And to import ViewPropTypes from 'react-native'.

This is happening in statement line 76 for inputWrapperStyle, strengthWrapperStyle, strengthBarStyle and innerStrengthBarStyle