[Freetel-codec2] Linear error correcting codes for entropy coding

[Gregory M. <gma...@gm...>]

I ran into these papers on using LDPC for block-entropy coding a while back:

http://www.princeton.edu/~verdu/reprints/Almost%20Noiseless%20Joint%20Source-Channel.pdf
http://www.princeton.edu/~verdu/reprints/dimacs2004.pdf
(at least the part of it prior to the BWT)

It wouldn't scale to the problems I was examining at the time, but it
might be applicable to codec2.