Allow modifying the color scale values

[jkomoros]

The logic now does manual color calculations, so you can't do it in CSS very easily.

They're currently hardcoded in _htmlForCell in map-visualization.js

[jkomoros]

• [x] have baseColor, positiveColor, negativeColor in the map data.
• [x] Have emptyColor, capturedColor, highlightedColor in the map data
• [x] Allow overriding all colors with color commands
• [x] setColor takes an object with name -> color
• [x] Support colors that are provided as rgb
• [x] Support colors that use rgba
• [ ] Suport colors presented as hsl
• [ ] Support color schemes. Pre-baked named sets, and also allow a color set to have a name to use that one
• [ ] Support active color (and activeCaptured color)
• [ ] Support changing the size of the strokes
• [x] Support CSS color keywords (including transparent)
• [x] Support arrays of [r, g, b], and [r,g,b,a]
• [x] Background moves to be set via setColors as well

[jkomoros]

npm package color-rgba looks exactly like what I want, but the polymer cli server doesn't handle its es6 imports of other packages.

Maybe snowpack? https://www.snowpack.dev/concepts/how-snowpack-works previously pika, as described here http://dplatz.de/blog/2019/es6-bare-imports.html

[jkomoros]

https://github.com/substack/parse-color also seems reasonable... but also doesn't work