More quant_band() reorganisation.
More quant_band() reorganisation.

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