Better color schemes

[dabreegster]

The game is pretty overwhelming visually. Map elements need more careful thought, especially zoomed in. It'd be quite useful to distinguish road type (the 3 colors zoomed out) also when zoomed in. There's a prototype in the sam_colors branch and various Google docs. It's also important to be friendly for various types of colorblindness. And there are some ideas floating around for different moods -- night, rain, autumn.

If anyone's particularly into colors, there are various google docs floating around I can dig up with notes.

[dabreegster]

Stumbled across https://www.printmag.com/post/12-major-cities-color-themes. It'd be neat to have a slightly different scheme for some cities.

[dabreegster]

Here are all of the pending tasks from #715.

Major:

• Overhaul night mode to use the same ideas
• Clean up parking_lane, normal_intersection, experiment fields
• calculate_corner_curbs is broken at 20th/Eaton and other places

Minor:

• Consider adjusting building outlines
• Consider a blueish color #74B0FC for parking lanes, or more markings to delineate
• Parked cars are maybe too faded / close to the asphalt color now
• Consider drawing a proper traffic signal icon unzoomed, instead of just solid black
• Consider moving road name labels off the road itself, Curve road labels #173

Refactoring:

• Fix up dashed arrows, removing overlap with the last dash and then using to_outline
• Refactor draw_signal_stage and DrawMovement::for_i

[dabreegster]

Further moodboard reference, heavily in the "sketch" style: https://www.theurbanist.org/2017/10/04/first-look-pike-pine-renaissance-act-1-concepts/