anchor.diff:  * index term that wraps should have a hanging indent (#645)
   * rename inherited_align to text_align? (and base_align to base_text_align?)
   * make sure any state is cleared after conversion, including attributes assigned
  -* FILE ISSUE: add support for file root / web requests for inline SVGs
   * when removing callout numbers, also remove the leading space so we don't mess up the highlighter
  -* should dpi be configurable?
  -
  +  - in particular, messing up highlighting for apache conf file
  +* make dpi configurable (controls the px to pt conversion)
  +* should we make :px the default units in to_pt? or require explicit units?
  +* use background color from pygments theme for source block
  +* block anchors should be positioned on same page as content if content is forced to new page
  +  - call theme_margin <type>, :top first
  +  - theme_margin should return distance moved (0 if advanced to new page)
  +  - pass effective margin as optional argument to add_dest_for_block to adjust placement
  +  - already handled for block images
  +* QUESTION: should we skip starting new page if image doesn't fit on whole page?
  +* consider using unlink on creation for tmpfile; see http://ruby-doc.org/stdlib-1.9.3/libdoc/tempfile/rdoc/Tempfile.html#method-i-unlink
  +* might be faster to not use TextDecorationTable lookup in to_styles (though it's only called once)
  +* if icon is specified, font-based icons are enabled, and value doesn't end in file extension, assume custom icon name
  +  ^ for core
  +* look into using close! on tmp file, which will safely unlink
  +* justify does not work in normal table cell (and does not inherit from base)
  +* support horizontal alignment of AsciiDoc table cell content (need to handle explicitly)
  +  - only relevant when using subtable since it must have width < cell width
  +
  +* -v doesn't turn on warnings soon enough to catch warnings in Asciidoctor/Asciidoctor PDF
   * allow front cover and back cover image to be defined in theme as fallback; document in theming-guide
   * keep together lines of a colist item?
  -* FILE ISSUE only nest document outline inside root node if doctype=article
  -* don't crash if image in running content is an unsupported format
   * support image URL (using resolve_image_path) in running content (what about data-uri?)
   * numbering for appendix subsections is not correct; should be A.1, A.2 (#627)
     - seems like an issue in core too
  -* BUG: implicit width of inline image (SVG only?) calculated incorrectly (see sandbox/issue-494)
   * BUG: http://asciidoctor.org[Asciidoctor] surrounded by smart quotes doesn't get translated to a link (as it should)
   * FILE ISSUE draw border for quote/verse block on right if text is aligned to the right
   * Prawn should not move cursor before placing image if image exceeds height of bounding box
  
positive.code: * "Incorrect number of arguments in 'SCN' command" happens when you add a stamp to an imported page
  * be mindful that layout_prose adds margin to bottom of content by default (important when working in a bounding box)
  * ttfunk does not support ligatures (e.g., fi -> ﬁ); we could do this manually in post_replacements
  
  == Notes
  
  
negative.code: * allow general settings for admonition icon to be set using admonition_icon key prefix (e.g., admonition_icon_size)
  * allow alignment to be set on discrete heading using role
  * submit pastie theme for Rouge upstream (PR sent, see https://github.com/jneen/rouge/pull/576)
  * SIMPLE: mark required theme keys (assume keys are optional by default)
    - required keys can never have a null value; most are set by base theme
  * allow font properties to be set for normal paragraph separate from base (need to think about inheritence)
  * allow alignment of list to be set separately from base align (and perhaps a hint in document) (#182)
  