anchor.diff:  * Properly scope attr and attr? lookups
   * Rename internal page_start and page_end attributes to pdf-page-start and pdf-page-end, respectively
   * Fix settings for table header cell
  +* Fix padding around content of quote block in default theme
   * Read theme file with UTF-8 encoding (#533)
   * Allow temporary image file to be deleted on Windows (#425)
   * Don't crash if theme file is empty (#551)
  
positive.code: * Document how to disable default footer from theme
  * Update explanation of WINANSI encoding behavior in theming guide
  * Restore support for Ruby 1.9.3 (#528)
  * Upgrade prawn-icon to 1.1.1
  * Upgrade prawn-svg to 0.25.2 (by way of looser version range)
  * Fix Ruby warnings
  * Document in README how image paths are resolved
  * Configure README for better preview on GitHub
  
negative.code: * Add page break before a book part (#329)
  * Allow running (header/footer) content to be arrange in columns (#449)
  * Prevent the SVG from modifying the document font (#494)
  * Implement decorative border for multipage quote and verse blocks (#270, #557, #558)
  * Encode anchors in hex that contain characters outside of ASCII range (#481, #301)
  * Clear the placeholder text used for an anchor to fix CannotFit error in table cell (#447)
  * Size the line number gutter correctly (accounting for width of largest line number) (#402)
  