Serialized window shape info

For each band, the shape of the right half of the MDCT window is saved, with 0 = soft window, 1 = steep window. The left half of the window has to be the same as the right half of the previous frame. As the first frame will not produce any sensible data, the left half of the first frame does not need to be defined.

• One bit: 0 = all bands use soft windowing, otherwise
  • One bit: 0 = all bands use steep windowing, otherise
    • One bit per band with spectral data: 0 = soft window, 1 = steep window