Files that import the selected file now get street routes too, from
the same single search (paths cost the same both ways), reversed so
they flow toward the selection. They draw as magenta dashes marching
inward with a pulse travelling along them, dashed on the minimap too.
Ribbon geometry moves into city.js and every ribbon keeps to the right
of its direction of travel, so an import and a dependent sharing a
street run in separate lanes instead of overlapping (tested).
Andy Dixon
8f3a3337b5