Added a few more contributors
Tweaked a translation string
Fixed some wrong namespaces
Fixed the inclusion of blank pages for printed books

  * If your edition sets the `two_sided: false` option, no blank
    pages are inserted in the book.
  * If your edition sets the `two_sided: true` option, some blank
    pages may be inserted to ensure that the important parts of the
    book start at an odd-numbered page.