anchor.diff:  * HIGH: use more thorough image path resolution
   * HIGH: move navigation_document method to Packager
   * HIGH: put shy marks after dashes to allow wrapping to occur in text justification
  -* HIGH: why can't id on chapter document be specified using +[#name]+ syntax? (it only seems to recognize +[[name]]+)
  +* MEDIUM: add landmarks nav list to nav.xhtml; see https://github.com/IDPF/epub3-samples/blob/master/31/moby-dick-mo-xhtml/EPUB/toc.xhtml
  +* MEDIUM: Kindle links to cover page when clicking on first chapter instead of first chapter page
   * MEDIUM: auto-space button in btn macro, or add icon & icon placement as attributes on btn macro
   * MEDIUM: move client sniffer JavaScript to file
   * MEDIUM: use the dfn element for defining a definition of a term (not just term class); see https://developer.mozilla.org/en-US/docs/Web/HTML/Element/dfn
  
positive.code: //^
  
  .Packager
  * HIGH: add NOTICE.adoc to e-book archive
  * HIGH: rework GEPUB so closures work more like in Prawn...perhaps using a wrapper
  * HIGH: minimize CSS (and any other assets worth minimizing)
  * HIGH: add back cover if specified
  * MEDIUM: set modified date explicitly
  * MEDIUM: use function to build and manipulate image paths
  * MEDIUM: issue warning if front-cover-image doesn't match proper syntax
  * support subtitle as separate from main title in package metadata
  * support collection title in package metadata
  
  
negative.code: = WORKLOG
  
  == TODO
  
  * add empty front matter page in kf8 version if one is specified to allow navigation to first entry from TOC
  * remove text justification hack (#92)
  * why can't we navigate to first chapter on Kindle from TOC?
  * add nav entry for cover if format != :kf8 ?
  * cleanup this sanitize XML stuff; move to Asciidoctor::Helpers?
  * allow role to be applied to chapter (which means the role must be on the document)
  * make sure every doc is assigned an ID (perhaps it already is) so we don't need to rely on the docname attr as a fallback
  * switch to epubcheck-ruby
   ** epubcheck-ruby 4.0.2
   ** supports options such as -q
   ** add -w option by default (perhaps allow additional options to be passed via the ebook-validate attribute)
  * store spine as map in references?
  * part vs chapter? a difference?
  
  * create a video to demonstrate Google Play Books read aloud reading complete sentences in books generated with Asciidoctor EPUB3
  
  