Codec state simplification
Codec state simplification

Making the preemphasis memory an array of two, removing unused fields

oneman/opus-oneman,oneman/opus-oneman,Distrotech/celt,Distrotech/celt,Distrotech/celt,dezelin/celt,mumble-voip/celt-0.11.0,mumble-voip/celt-0.11.0,mumble-voip/celt-0.11.0,dezelin/celt,dezelin/celt,oneman/opus-oneman