Add example for 3rd-party RN module usage

[elliottsj]

To reduce some confusion that some users have had, we should add usage of 3rd-party RN module(s) like react-native-camera to an example project.

[jrm2k6]

@elliottsj I remember talking about that in this issue https://github.com/mjohnston/react-native-webpack-server/issues/57 The part where you specify the include array. If this is about the same thing, I am happy to create an example for it and submit a PR.

[jeffcressman]

+1