[librsvg] (37 commits) ...Merge branch 'text-refactor'

[Federico Mena Quintero <federico src gnome org>]

Summary of changes:

  6047295... NodeChars.measure(): Oops, actually add the width to the ru
  0386078... NodeChars.measure(): Return a value; don't mutate an argume
  266ed94... text.rs: Don't pass a mutable length to all measure() funct
  a6492f4... text.rs: Don't mutate the arguments of the render() functio
  c55511b... text.rs: Don't obviate TextAnchor::End with "_"; spell it o
  b550fdf... rsvg-view: Allow quitting the program with Ctrl-Q or Ctrl-W
  e7c2896... Split into Span and MeasuredSpan
  10094bc... Factor out NodeChars.make_span() from duplicated code
  b141150... PositionedSpan: move the span positioning logic to here
  91a4019... PositionedSpan: store both the nominal position and the ren
  f091ea2... Chunk: remove the final positions, leave only the specified
  e97cbef... text.rs: Start logic to turn a NodeText and its children to
  251400f... text.rs: new MeasuredChunk, analogous to MeasuredSpan
  77b2e91... PositionedChunk: implement the layout logic
  9a54532... text.rs: Reorder the impls a bit
  af22df9... MeasuredChunk: compute the advance of all the MeasuredSpans
  2bb03ab... WritingMode.is_vertical(): new convenience function
  f122dd2... PositionedChunk: Adjust the position based on the text_anch
  06a81e1... text.rs: Oops, use the child when iterating, not the parent
  72100df... NodeText.draw(): implement in terms of chunks and spans
  20a483e... children_to_chunks(): Do not create chunks here; assume the
  4c6ef0f... NodeText::draw(): Use the current's chunk position if avail
  7a05488... NodeText::draw() - Oops, use a layer so the text node gets 
  dbde789... text.rs: Remove the old code
  b69cd27... rustfmt
  a4de907... NodeTSpan: make the dx/dy fields Option<Length>
  be7f36c... text.rs: Implement dx/dy for NodeText and NodeTSpan
  525aa6f... Annotate each Span with its nesting depth within the topmos
  a7386aa... Remove the C-callable functions
  010f08c... Implement tref
  a466842... NodeChars.to_chunks(): Extract this common function
  a4d94e2... Add text-tref-01-b.svg to the tests
  1528ed9... Add text-tref-02-b.svg; make all nodes accept NodeChars chi
  81d182f... Add text-tref-03-b.svg
  8f7d4f9... Move failing test to ignore-filters-displace-01-f.svg
  1e15b3c... text.rs: Remove debugging printlns
  bba089f... Merge branch 'text-refactor'