Use literate programming + Rmd slides

[mine-cetinkaya-rundel]

Use of literate programming via Sweave will likely not be very helpful at this point, but the slides could benefit from a xaringan / Rmd conversion. This would allow us to test and maintain the code easily and provide a good starting point for faculty who are R users.

One issue is that we might not want to remove the PDF option completely, and we don't want to maintain two code bases, so this would require a solution where slides can be written to PDF and HTML easily from the same source files.