v0.7.74

• Added -style options stroke-linecap= (round, butt or square; dashed lines default to butt) and line-fade=, which fades a line in from transparent along its tail.
• [web] Added line cap and fade controls to the line style panel.
• Added diverging classification to -classify: pivot= (a value, median, mean or auto), pivot-range=, no-pivot-class, pivot-class and classes=<below>,<above>. Each side of the pivot is classified separately, with an optional pivot class in the center color.
• Added interpolation=oklch and vibrance= options to -classify, for interpolating colors in the OKLCH color space.
• -classify continuous now works with pivot=. A list of N colors now gives N-1 intervals, so that each color is a stop to guide the interpolation (previously N colors made N intervals).
• -classify method=categorical now repeats a list of colors that is shorter than the list of categories, and empty values are no longer categories (they get the null value).
• [web] Added a Color palettes panel, opened by the Palettes button beside the polygon fill color. It colors polygons by a data field using sequential, diverging or categorical schemes, preset or custom color ramps, and classed or continuous colors.