anchor.diff:  * make alternating page title position optional (via theme?)
   * BUG: page numbers are off in Clojure Cookbook
   * image in header / banner (need to implement a masthead)
  -* do CMYK values work for colors?
  +* do CMYK values work for colors? no, but we should support an array value
   * fix passthrough placeholders that get caught up in syntax highlighting (see https://github.com/asciidoctor/asciidoctor/blob/master/test/blocks_test.rb#L2258-L2277)
  +* we could eliminate some of the tags we're currently matching in the formatted text parser (e.g., link)
  +* add Preamble to TOC
  +* NOTE prawn-svg supports loading from a URI
   
   * enable pagenums attribute by default (may require changes to how we handle attributes)
   * start page numbering on first page if no title page
  
positive.code: = WORKLOG
  
  == TODO
  
  * use Groovy language specification as case study to find corner cases
  * allow pdf-page-layout (portrait || landscape) to be set in document
  * attribute or role to control table shading (all, even, odd) (or call it striped like bootstrap?)
  * make conum glyphs configurable in theme (use reference table to resolve)
  * make room for large numbers in ordered list (workaround is to set a larger outline_list_indent in theme)
  * add pdf page import support to the image block macro (file issue)
  * do we still need the converter hack in convert_content_for_block? (seems to be needed for admonitions)
  * avoid getting an empty last page (example: colist at bottom of page can cause this)
  * utility to coerce the color value transparent to nil (better handling in general)
  * quote all color values in reference themes
  * cjk and/or multilingual support
  * description list term should keep together with content
  * GhostScript Tiger SVG is reporting incorrect height when embedded; bug in prawn-svg?
  * hardbreak in table cell results in extra endline (likely not normalizing cell content)
  * don't create new page if content overflows and we're on the first page
  * parse pdf-page-size syntax 8.5in x 11in (or optional square brackets)
  
negative.code: * reorg Prawn extensions (see prawn-table for example)
  * rename "theme" to "style"?
  * restrict custom theme path to jail (or load from load_path)
  * implement convert_toc
  * can get orphan conum if starts on last line of page (fixed already?)
  * only create title page if doctype=book
  