use of a single file for the "programming with gtkmm" book

[lecas malecas <darkiiiiii gmail com>]

Hi,
currently the gtkmm book uses docbook, and has all content in a single
file (root/docs/tutorial/C/gtkmm-tutorial-in.xml), which makes it
really hard to edit it.

What I'm wondering, is why isn't each chapter in its own file, it
would facilitate changes.

Also, why is docbook used instead of plain html?
Html is more known, so it would be easier to edit as-well.

thanks