fdkaacenc: Refactor layout selection code
This was refactoring I did trying to improve the position assignment code in fdkaacdec (which is in the aac-more-multichannel branch). I'm not happy with the latter yet.
This was refactoring I did trying to improve the position assignment code in fdkaacdec (which is in the aac-more-multichannel branch). I'm not happy with the latter yet.