minify SVG images from documentation
The tarball currently distribute 5.8MB of SVG files in
svgo would halve that to 2.9MB.
Not included in the distribution tarball, but present on the Debian packages are also 6MB of SVG files in
doc/spot.html/. Those can be reduced to 4.8MB.
Note that, at least on
svgo has to be run with
--disable=removeViewBox otherwise SVG displayed with
<object> are incorrectly scaled.