- Put tables in aactab.c, table declarations in aactab.h, structures and definitions in aac.h
 - mainvlc -> vlc_scalefactors
 - books[] -> vlc_spectral
 - ff_code -> ff_scalefactor_code etc
 - ff_code# -> ff_spectral_code# etc
 - ff_spectral* -> *ff_spectral_codes[], *ff_spectral_bits[], ff_spectral_sizes[]
 - check value of index*dim against codebook_vectors[] lengths in decode_spectrum()
 - realign somewhere near ff_aac_num_swb

- Don't use context for function arguments
- Check presence of things before calling functions rather than within them
- Order function arguments consistently (inputs to outputs or vice versa)
- Channel configuration stuff