Combine plot-ps-interactive? and plot-pdf-interactive? into plot-ps/pdf-interactive?
Rename plot3d-ambient-light-value -> plot3d-ambient-light
Fix off-by-one 2D plot area clipping
Add warning to docs about 'fit' disappearing
Stop providing 'fit', 'derivative', 'gradient' and 'make-vec' from the 'plot' module
Merge into 5.2