2nd edition of Learning React Native

This release includes the code samples as provided in the 2nd edition of Learning React Native.

Code rewrites for the second edition

2.0.0-alpha

remove redundant map

v1.0.0: Updated to use react-native 0.26.3

• Update all code samples (except for PlatformSpecific) to use react-native version 0.26.3
• Use ES6-style classes and module definitions where appropriate

First edition of Learning React Native

Code samples as published in the first edition of Learning React Native.