anchor.diff:  * allow alignment of list to be set separately from base align (and perhaps a hint in document)
   * due to order of loading, getting warnings when redefining methods in Asciidoctor core
   * prawn-pdfimage https://github.com/packetmonkey/prawn-pdfimage
  -* rename ThemeLoader to ThemeReader?
  +* rename ThemeLoader to ThemeReader (or ThemeManager)?
   * document autofit option on verbatim blocks
   * document how to extend the converter, use Prawn
   * using tabs instead of spaces for source code indentation allows leading whitespace to be preserved when copying
  +  - is this always the case?
  +* normalize step leaves space after endline (i.e., `\n `) at a hard line break (doesn't seem to affect flow)
   
   * *margin per heading level* (see https://github.com/asciidoctor/asciidoctor-pdf/issues/176)
   * document how to override the Ruby code to get custom styling in the theming guide
  
positive.code:   - get import_page to stop adding an extra page
    - blank page after title page if media=print
  
  * document missing keys in theming guide for 1.5.0.beta.1 (table seems to missing some)
  * enable key table_font_style
  * check that color of table edges set to table_grid_color??
  * create value type for font style and font alignment for theming guide
  * force encoding of theme to UTF-8 (particularly for keys related to content)
  * be more consistent with how examples are shown in theming-guide.adoc (do we show last segment only?)
  
negative.code:   - perhaps progit2 as well; others?
  
  == TODO
  
  * document show-link-uri in table on asciidoctor.org
  
  * recto/verso margins
    - account differences in top/bottom margins on recto/verso pages in running header/footer
  