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.
This commit includes a bunch of minor things:
- change keyboard shortcut to 'E' to not conflict with anything
- move `disabled` check from operation into action and simplify
- use `actionMoveNode` to place the detached node at the mouse cursor
- disable the operation if the node is connected to hidden features
- lots of code simplification
- make the icon more centered
This lets us break closed ways at their connecting node in the few situations where
we actually want that behavior (disconnect action for circular non-area ways)
