anchor.diff:  * allow multiple font dirs to be specified using the pdf-fontsdir attribute (#80)
   * fill and stroke bounds of example across all pages (#362)
   * allow page background color and background image to be used simultaneously (#1186)
  -* allow theme to specifiy initial zoom (#305)
  +* allow theme to specify initial zoom (#305)
   * strip surrounding whitespace from text in normal table cells
   * allow attribute references to be used in image paths in theme (#588)
   * resolve variables in font catalog in theme file
  
positive.code: * set line spacing for non-AsciiDoc table cells (#296)
  * consider all scripts when looking for leading alpha characters in index (#853)
  * don't create title page for article doctype unless title-page attribute is set (#105)
  * don't show article title if notitle attribute is set (#998)
  * generate name section for manpage doctype automatically (#882)
  * remove unprocessed passthroughs in literal cells
  * apply font style from theme to formatted text description list term (#854)
  * prevent tempfile for remote image from being deleted before it's used (#947)
  * handle case when uri to make breakable is empty (#936)
  * add support for frame=ends as alternative to frame=topbot on table
  * allow table frame and grid to be set globally using the table-frame and table-grid attributes (#822)
  * disable table stripes by default (#1049)
  * allow table stripes to be enabled globally using table-stripes attribute (#1049)
  * use new logging subsystem, if available; otherwise, use shim (#905)
  
negative.code: Enhancements::
  
  * make delimited blocks breakable by default; require the `unbreakable` option on the block to retain the previous "`keep together`" behavior (#2004, #578, #509, #240)
  * add support for the `unbreakable` option on a table to prevent it from being split across pages (#2022, #871, #819, #331)
  * add support for the `breakable` option on a table (special case) to keep the caption and ID with the start of the table (#2022, #993)
  * implement smart bottom margins on blocks to prevent extra space below blocks, particularly nested blocks (#1515, #1513, #1845)
  * drop support for `top-margin` key on block and prose categories in theme; space between delimited blocks and lists now controlled using bottom margins only (#1515)
  * allow location of anchor for block to be positioned relative to content using `block-anchor-top` key in theme (#2013)
  * allow page numbering and running content to start after first page of a document without a title page by assigning an integer to the respective `start-at` theme key (#1644)
  * allow page numbering and running content to start after toc (wherever it's placed) by assigning the keyword `after-toc` to the respective `start-at` theme key (#1763)
  * allow theme to configure page numbering to start at cover (#1727)
  * allow the front and back cover images to be defined in the theme (#1584)
  * allow the front and back cover images to be specified as a data URI (#1584)
  