This generalizes the oneway arrow logic for adding SVG markers along a
line. Using that functionality, certain tags get arrows on their
right-hand side, indicating which side is "inside", e.g. the
right-side of a cliff is the lower side.
The list of tags considered to be sided (unless there's a
two_sided=yes tag) is:
- natural=cliff
- natural=coastline
- barrier=retaining_wall
- barrier=kerb
- barrier=guard_rail
- barrier=city_wall
- man_made=embankment
The triangles attempt to be reminiscent of the triangles used for
rendering cliffs on OSM (and elsewhere). The different tags get
different renderings (e.g. colors that match the main way, and
different spacings). In addition, natural=coastline is special-cased
to have blue markers (despite having a green way), to emphasise that
the "inside" of a coastline is the water.
Fixes https://github.com/openstreetmap/iD/issues/1475.
(closes#4669)
Now instead of creating MultiLineString targets, we just create a bunch of
LineString targets. This makes the code simpler, and anyway the entity is
still there in `properties` for drawing code to decide what to do with the target.
Incidentally, this change allows iD to support an extrusion operation.
(Because each way segment has its own unique GeoJSON target now)
This makes the code a bit more consistent and lets us avoid some
hacky and probably non-performant things:
- abusing CSS classes in the draw/drag datum functions (classed `.target`)
(is this thing target? just check d.properties)
- regexing the id for `-nope$`
(is this thing a nope target? just check d.properties)
- using context.hasEntity to get a the real entity
(is this thing a real osmEntity? just check d.properties)
- fixes code like the restriction editor which uses fake ids for split ways
