Add support for Chapters / Markers (dMC)

[flips]

It would be cool if you would consider adding support for WAV/FLAC markers, that
they would survive as MP3 chapters when converted ...

[brandonjp]

Ditto on this.

Oof! Last month, I down-sized a bunch of old MP3 Audiobooks from 320kbs Stereo to 96kbs Mono MP3 and just assumed everything was great until last week I tried skipping to a chapter. Went back and checked that all of the files had lost chapters. And the originals are long gone now :(

Regardless, would be a great addition for the future!