huff/cdic support

[clee]

LZ77 is great, but the majority of my purchased Mobi/AZW3 files are huff/cdic compressed.

I have some documentation on the format I managed to put together.

[vv9k]

I’m definitely interested in seeing this implemented in this crate. I will dig into the topic once I have some free time.

[vv9k]

~~Do you by any chance have some samples of eBooks that are huff compressed and you could share with me? It would definitely make the testing easier.~~

Thanks for the sample!

[vv9k]

For reference implementation: https://github.com/kovidgoyal/calibre/blob/master/src/calibre/ebooks/mobi/huffcdic.py

[clee]

Also: https://github.com/bfabiszewski/libmobi/blob/public/src/compression.c

[vv9k]

Nice, C implementation will be much closer to what we are looking for.

[vv9k]

This is currently in the making thanks to a PR from @philippeitis - #29. Will have to work some issues out but there is light on the horizon :)