Add 15-colorblind friendly palette

[briochemc]

Not sure about how it should be named, but this palette could be a nice addition for many categories I guess:

Link to poster: http://mkweb.bcgsc.ca/biovis2012/krzywinski-visualizing-biological-data.pdf

Not sure about copyright either.

[cormullion]

Reading this suggests that a max of 8 colors is preferred.

This also recommends the following:

It's easy to add those with these names...

[briochemc]

Yes, I agree, my response on slack literally minutes ago was "11 categories is a lot to ask for a colorblind-friendly palette". But then I remembered this one, and thought it could be useful for, well... extreme cases of many categories!

[briochemc]

Ha I also remember reading the Paul Tol blog (https://personal.sron.nl/~pault/#sec:qualitative)! These are also pretty nice and would be a nice addition IMHO 😄

[cormullion]

I added a few, currently on master. Docs will show:

[briochemc]

I think this can be closed then, no? Or should it stay open until this makes it into a release?

[cormullion]

No problem - thanks!