anchor.diff:  
   == TODO
   
  -* remove text justification hack (#92)
  +* remove text justification hack (#92) (PR sent)
  +* warn in case when target of inter-document xref can't be resolved, but xref has explicit text
  +* don't add image from front matter if already referenced by chapter
  +* add document filename to warn messages
  +* look for front-matter.html relative to docdir (or base_dir?); also allow front-matter.xhtml
   * cleanup stashes
   * change references[:spine] to spine_document property
  -* use standard warning format in packager
  -* note that EPUB that uses hexidecimal character references doesn't validate
  +* add helper to resolve imagesdir
  +* support inline SVG
  +* describe the leveloffset setting in more detail
  +* link to https://medium.com/@sandersk/responsive-ebook-design-a-primer-8bba01328219 in style section in README
   * why don't we just use the chapter filename as the id?
   * only uppercase document title if detected in CSS
   * add empty front matter page in kf8 version if one is specified to allow navigation to first entry from TOC
  
positive.code: * 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
   ** I believe this is already true; just remove hack
  * only add svg property to spine item for front matter file if SVG is detected
  * should we enable hyphens in non-Kindle?
   ** we can reenable once we confirm it doesn't crash Kindle for Mac
  * switch to epubcheck-ruby
  
negative.code: 
  * conversion of single file (no master document)
  * package images referenced by content
  * how custom CSS is specified
  
  == NOTES
  