0.12.0

This release includes a few new features, such as the possiblity to
include Markdown files as section/subsections and not only as chapter,
experimental support for superscript and subscript, and yet more
experimental support for writing interactive fiction.

• Book configuration file:
  • It is now possible to include subchapters using the -- command
    (with one dash per sublevel: --- foo.md will include foo.md as
    a subsection).
• Markdown:
  • Added support for superscript and subscript features, using
    respectively foo^up^ or bar~down~ syntax.
• New options:
  • rendering.chapter: change what is displayed in place of
    "chapter".
  • rendering.part: change what is displayed in place of "part".
  • html.chapter.template and html.part.template allow to tune a
    little how the chapters and parts are displayed in HTML.
  • tex.hyperref, if set to false, will disable hyperrefs for
    local links. Can be useful for some files.
  • crowbook.html_as_text, if set to false, will not treat HTML as
    text but ignore it.
  • subtitle, as its name suggest, set the subtitle of a book.
  • crowbook.markdown.superscript can enable or disable superscript/subscript "extension".
• Rendering:
  • Change the way chapters are displayed by default.
  • PDF output now has a better-looking (hopefully) title page.
  • Internal links are a bit more flexible, e.g. if you link to
    Readme.html it will now try to link to the chapter corresponding
    to Readme.md.
• Bugfixes:
  • LaTeX:
    • Fix bug in syntax highlighting.
    • Fix label placements (and thus navigation inside PDF document).
  • EPUB:
    • Add unnamed but numbered chapters to the TOC.
    • Fix HTML escaping issue for chapter titles.
    • Fix the way parts were handled in the TOC.
  • Book configuration file:
    • Fix issue when setting custom number for parts.
• Crowbook now requires rustc >= 1.17.0