v0.35.0

Added

• GridElement — non-plot PlotGrid cells (patchwork's
  wrap_elements, #378): GridElement::fixed(svg, w, h) scales a fragment
  drawn in its own w × h box into the cell keeping its aspect;
  GridElement::fill(|w, h| svg) renders at the cell's real size. The cell
  is a nested <svg … data-cell="i">, takes part in widths/heights and
  tag_levels, and is skipped by axis_collect / collect_legends; the
  | / / operators accept it. Markup is inserted verbatim.

Fixed

• Inside legends (LegendPosition::Inside, legend_inside_auto) are inset
  by legend_margin from the panel edges, and the title — drawn centred on
  the legend origin — no longer sticks out above the box (it was clipped in
  a top corner); a colourbar's bottom label overhang is counted too (#377).

Changed

• Breaking: GridCell has a new Element variant (exhaustive matches
  need an arm).
• Inside legends with a non-zero legend_margin sit that margin further
  in from the panel edge.