TODO: In any order

Big list, but a lot of it can be done fairly easily with some old code.
Note: most of these issues are quite old, and it's not clear who submitted them
in this file and why and/or if some of them are fixed in the meantime. The
ChangeLog might give some insight on this though.

- DONE: Add frequency cutoff filter
- DONE: Add ADTS headers
- DONE: Write GUI
- DONE: Add TNS
- DONE: Add LTP
- DONE: Add backward prediction (MPEG2-AAC)????
- DONE: Test (and maybe fix) sample rates other than 44100 Hz
- DONE: Test (and maybe fix) multichannel and mono support
- DONE: Figure out how to read and write ".mp4" format
- DONE: Write documentation for library interface
- DONE: Improve command line tool
- DONE: VBR quantizer
- DONE: Speedup
- Done: Clean up psychoacoustics code
- Done: Add Window shape switching

- Add PNS
- Add IS
- Add bit reservoir control
- Add pulse coding (?)
- Rewrite noiseless coding (now taken from old version) (?)
- Better grouping support (?)
- Fix short block psychoacoustics (?)
- Fix TNS (hans-juergen, Oct 17, 2004)
- Fix LTP (hans-juergen, Oct 17, 2004)
- Fix Main (hans-juergen, Oct 17, 2004)
- Add resampler and downmixer (hans-juergen, Oct 17, 2004)
- Add HE AAC (hans-juergen, Oct 17, 2004)
- Fix mysterious crash/freeze with some decoded WAV files on
  Linux: endianness? TNS? M/S? decoder bug? (hans-juergen, Oct 17, 2004)
- Fix default ABR cutoff frequencies at different bitrates
  (hans-juergen, Oct 17, 2004)
