[FFmpeg-devel] Implementation of AAC decoder (fixed point)

[Nedeljko Babic]

Changes to libavutil are moved and split in two new patches.

Changes are made so the code is buildable after every patch is applied, so some
patches became redundant.

Most of the changes requested in last review implemented.

The documentation about implementation of butterflies_fixed is not changed.
I saw the comment later and I was not sure what was asked exactly since there is
no shift in implementation of this function.
I will make additional change in this patch if needed.

Please have a look.

-Nedeljko