anchor.diff:  * upgrade to kindlegen 2.9.6 (only works for Ruby >= 2.0.0)
   
   //^
  -
   .Packager
   * HIGH: retain file name of original chapter file (otherwise, it can break interdoc xrefs)
   * HIGH: add NOTICE.adoc to e-book archive
  
positive.code: * customize id of <item> elements in epub manifest?
  
  //^
  
  .CLI
  * augment Asciidoctor::Cli::Options with --validate and --extract options, pass on as attributes
  
  //^
  
  .Asciidoctor
  * patch sanitize of any section or block title into Asciidoctor
  * generate id for chapter <= make part of Asciidoctor parsing API
  * patch Asciidoctor to replace smart quotes w/ unicode chars instead of entities (glyph replacement mode)
  
  //^
  
  == REVIEW
  
  * conversion of single file (no master document)
  
negative.code:   - see if Google Play books supports JavaScript and epubReadingSystem (no, but adds its own class to body)
  * CRITICAL: use a following sibling selector for :first-line in abstract so it works when page is partitioned (e.g., in Google Play Books)
  * CRITICAL: add support for different numbering systems (lowergreek, etc)
  * CRITICAL: surround prose in <span> (e.g., simple <dd>) which is not nested in <p> or <div> so iBooks can change the font
  * HIGH: kindlegen no longer strips <header> elements, so we can drop our div wrapper hack
  * HIGH: don't set text color so light on monochrome devices (use media query to detect)
  * HIGH: make justify-text a class on body that can be controlled from AsciiDoc attribute (don't use word joiner in this case)
  