Suggestion: 'traffic' color ramp

[ThierryO]

I've created a color ramp from dark red over medium orange to light green. Inspired by traffic lights, hence the name. I think it should work for color blind people and grayscale print. Below is a ten color palette. The plot shows each color multiple times in an arrangement that places each color next to every other color. This makes it easier to see how easy one can distinguish a pair of colors.

I'm willing to write a PR.

Simulated deutan model

Simulated protan model

Simulated tritan model

desaturated