Also update the add-on to allow for configuration of
potrace's alpha settings, which controls how strongly
it favors straight lines. This makes things like buildings
look a lot nicer.

Also updates the add-on some more. It can now
assign materials based on face maps, which the
Building Tools add-on creates automatically

Also update the Blender scripts to use red/green/blue areas
instead of light and dark ones. This also allows for
three colors now.

Also fix broken attribution for utility poles

This also includes new scripts for generating some data -- but I am going
to migrate the actual generator scripts to another repo soon

Firefox won't draw SVGs to a canvas correctly without width/height
attributes (even if a viewBox is present). This commit inserts those
values where needed and removes the Firefox check from the click
detection code, so it works properly (and screenshots are fixed, too).

units