update README link lib (https://github.com/EstebanFuentealba/react-native-share/issues/58#issuecomment-248521758)
update README link lib (https://github.com/EstebanFuentealba/react-native-share/issues/58#issuecomment-248521758)

EstebanFuentealba/react-native-share,EstebanFuentealba/react-native-share,EstebanFuentealba/react-native-share,EstebanFuentealba/react-native-share