Create interactive books for the web and PDF export support

I’m working on a book about publishing for technical people (still haven’t settled on a title). This project looks cool, and I like the approach, but I have a couple of notes:

- It looks like it has been a while since the last update, and lack of ePub output would be a dealbreaker for me. - AsciiDoc doesn’t support the “interactive” part of this, but it is a text-based format with tools that will take you all the way through to publication - AsciiDoc will also let you do indexes for print, which is something very few other tools like this will do

All of that said, I do like the idea of being able to make a book with interactive elements, but worry that doing so would require being very careful to make it so that those interactive bits aren’t required to get value from the book, if it will also be in print.