Create 8x8 superpixel ChunkDivider type
Parameterise the Superpixel class.
Make Superpixels go top-to-bottom (but right-to-left)
Fix antialias calculation bug (was visible as vertical artefacts in the Vertical10px / Superpixel dividers)
Use 64x64 superpixels for the main window. Stick with Horizontal10px for the CLI.
Hide the detail of the SaveAsPNG chunk divider from callers. Stay with a Horizontal10px.
Fix the HUD showing incorrect maxiter.
Create HUD erase interface.
Update the HUD at the start of a plot, for consistency.
It doesn't make sense to allow undo through a resize.
Fix Undo-during-plot crash and improve cosmetics
Don't bother to stop the plot on a delete event (^Q doesn't)
Improve Stop cosmetics - remove needless blocking call