anchor.diff:  
   == Implementation
   
  -* should we read SVG file using UTF-8 encoding; REXML seems to handle encoding
  +* should we read SVG file using UTF-8 encoding; or does REXML handle encoding?
   * can we leverage before_rendering_page callback on table?
  +* should we use move_past_bottom in some places instead of start_new_page?
   
   === Design
   
  
positive.code: 
  == TODO
  
  .1.5.0.alpha.13
  * ensure book chapters and parts start on recto page when @ppbook (using start_new_chapter / start_new_page methods?)
    - need a way to add excludes
  * should we use the term "column" instead of "placement" in running content
  
  //--
  * generate fonts without PS Glyph Names to reduce file size (waiting PR #550 to be marged)
    - create script that can generate fonts entirely from original font source
  * FIXME if a page is left empty, writing running content on it causes ghostscript to report an error
    - problem is no color space is set; can call update_colors to fix
    - maybe have a skip_page helper?
    - doesn't yet apply since we don't yet insert blank pages in content
  * SIMPLE: document vw/vh measurement units in theming guide (make it clear it only applies in certain cases)
  * SIMPLE: in theming guide, emphasize not using the fallback font when working with very large documents; explain that default theme uses a fallback font
  * rework resolve_image_path API so it's more logical; override based on type of first argument; document as option
  * document how to test / use a PR
    - see https://github.com/asciidoctor/asciidoctor-pdf/issues/462#issuecomment-246200953
  * FILE ISSUE break printed URIs at each forward slash (and perhaps at ? and & too)
  * add empty? method to Page (instead of page_empty? on document)
  * SIMPLE: add warning that AsciiDoc table cell content is not supported; print as raw source
  * implicit width of inline image calculated incorrectly (see sandbox/issue-494)
  * FILE ISSUE in prawn-svg not to move cursor (maybe an option?)
  * FILE ISSUE: prevent import_page from adding an extra page; leaves blank page when placing two inserts in a row
    - have import_page first delete current page if page is empty
  * autowidth causes cells in header row to break word (wraps by char to fit; does not expand table)
  * dry_run should start at cursor of main document (or as option); total height calculation would need to be revised
    - this should fix height calculation when content is split over a page break (leaving small amount of excess)
  * allow height of inline image to be set to line height (perhaps 1em?)
  * add support for format attribute on image macro to image-related attributes such as title-page-background-image
    - support explicit image format for cover page image and page background image
  * need some sort of post_construct method for converter that receives document
  
negative.code:   - in fact, must account for every page or else numbering lags behind when scrolling document
  * if we set the vposition on image to a numeric value, it skips the overrun check that happens internally
  * any instance variables referenced by converter methods for inline nodes could get accessed before the converter for document is called
  * Evince throws warning when printing PDF if & is used in document title; but this is valid according to the PDF specification
  * Prawn drops fragments with empty text (hence the need to use zero-width space)
    - analyze_glyphs_for_fallback_font_support drops fragments with empty text
    - later on, initialize_wrap drops fragment with empty text
  * use term "page number label" to refer to the visible, printed page number (not the implicit page number)
  
  == Potential Optimizations
  
  