Update book making command. Switched to A5 portrait. In landscape it stretches the image to fit the width, and that causes a lot of longer tunes to become too high to fit properly on the page. Build the book in a separate build directory. The build generates lots of .abc files and so forth, which it is convenient to have elsewhere so you can ignore them. I did experimend with \abcinclude, but that has a lot of expectations about the files being in the current directory. If a tune has multiple titles, pick the first. Adjust abcm2ps options to preserve the line breaks in the ABC.