Consider generating Scala 2 compatible code

[ekrich]

I have put quite a bit of effort but have not been able to complete the update to scala-native-bindgen. Now that you created this project, my motivation to complete it has evaporated. It is quite a beast and hard to debug.

Ref: scala-native/scala-native-bindgen#195

There are quite a few examples and results that might be useful - not sure how you are testing but the test approach there is pretty interesting.