chore: update android docs for rn 0.30+ (#146)
chore: update android docs for rn 0.30+ (#146)

* update export

* update undefined var

* add fb setup link for android

* chore: update android doc for rn 0.30+

leonacky/react-native-facebook-login,lwhiteley/react-native-facebook-login,leonacky/react-native-facebook-login,lwhiteley/react-native-facebook-login,leonacky/react-native-facebook-login,lwhiteley/react-native-facebook-login