horizontal definition lists desired

[gdamore]

I've been struggling with using tables to stand in for definition lists, and I've been really dissatisfied with the results with the epub generator. (The table layout handling is not nearly as nice as it is in PDF, probably because of tighter constraints in the ebook layout).

At any rate, I think what I really want is functional definition lists that honor the [horizontal] style, when they can. I have some long lists today, and having terms and definitions on separate lines reduces readability and "compactness". (The PDF output format has this problem too, it seems only the html backend does this correctly.)

[gdamore]

I have some code that demonstrates this ... I'll post a PR, but I suspect it needs more massaging before it is included.