[panelset] Printing slides with panelsets

[gadenbuie]

Maybe doing some JS magic to add slides for each panel, see https://www.tjvantoll.com/2012/06/15/detecting-print-requests-with-javascript/

[gadenbuie]

I've worked out a "low-tech" solution that uses {chromote} and essentially fakes a → press to walk through the slides, printing each slide to PDF. Due to the dependency requirements, I don't think it's a good fit for this package, but I've published the source here: https://www.garrickadenbuie.com/blog/print-xaringan-chromote/

The advantage of this approach is that it will work with just about any slides, no matter how complicated, as long as you can walk through slides one-by-one using →.

I'll leave this issue open as I might choose to pursue detecting a print request to add print CSS or re-arrange the slides.