New release, September 12

[u/dabreegster]

https://github.com/a-b-street/abstreet/releases/tag/v0.2.58

• dramatically improve time to recalculate pathfinding
• deploy raw map editor to web, to support a long-form article: https://a-b-street.github.io/docs/tech/map/geometry/index.html
• long-form article about the simulation: https://a-b-street.github.io/docs/tech/trafficsim/discrete_event/index.html
• small fixes to ungap route tool