This yields a 10x paint performance increase at
#map=18.88/38.85208/-76.72632, as measured with
Chrome Canary's "Continuous Page Repainting" mode.
Fixes#885.
Due to differenced redraw, midpoint.ways was getting stale,
so sometimes dragging a midpoint didn't add the new node to
all ways. Better to calculate participating ways when needed.
This also simplifies the code for adding a midpoint via double
click. It does make filtering midpoints on redraw a bit more
expensive, but a cursory profile didn't show it being a problem.
Fixes#763.
This avoids a duplicate full redraw at the end of a drag pan. The
redraw triggered by mouseup.zoom now cancels the pending debounced
redraw.
Also, bump the debounce interval to 300ms, which helps avoid full
redraws during scroll zoom, making it more responsive.
Multipolygon relations report their geometry as 'area' and are rendered
as such. However, they do not render a stroke. The stroke rendering
will come from the individual lines, which are given the tag
classes of their parent relations, allowing them to have a stroke
style matching the style of simple areas with the same tags.
Untagged circular ways are no longer considered areas. This prevents
an untagged inner way of a multipolygon from rendering as an area and
is consistent with how P2 and JOSM treat them.
In the CSS, it's no longer necessary to deal with multipolygons
explicitly in selectors. But keep in mind that area boundaries can
now be rendered either as lines or as area strokes. In most cases
the selector should be `path.stroke.tag-_____`, i.e. an explicit
`.area` or `.line` classes should not be included.
Finally, the parent ways of selected multipolygons are given the 'selected'
class.
