And clean up some other things that RDP does better.
Fallout from regenerating everything:
- Enfield borough crashed, so removed it
- All UK scenarios are now much bigger, due to the changes in #853 being
picked up
- Poundbury gridlocks now due to that
too far, by not trying to trace near railways or cycle-only
bridges/tunnels. This is an imperfect heuristic, but it makes
significant progress in most maps.
intermediate results can't be turned into a polygon. It'll break
something later. #841
There's a particular bug where a perimeter can be turned into a polygon,
but after collapsing internal dead-ends, it can't.
If we don't do this, the LTN select boundary UI crashes, and reasoning
about block -> neighborhood mappings gets very hairy. I'd like to
address all the root causes of failing to make a polygon, but until
then...
TRADE-OFF: it _really_ slows down the select boundary UI.
along the perimeter of broken intersections.
There are cases where intersection geometry is a little bit broken,
jutting out a bit and touching a road. It's more robust to still produce
a reasonably shaped block in these cases, instead of totally give up.
Visual inspection and the goldenfile VASTLY improved!
1 lane (usually a cycleway or footway). This correctly produces a few
more blocks in some maps -- as the goldenfile diff (and manual
verificaton) shows!
Also allow jumping from LTN browse to debug mode, to conveniently work
on blockfinding problems.
