This function will build a handout and save it to files/code-handout.R
in your lesson website. This will build with your website if you enable it
with options(sandpaper.handout = TRUE)
or if you want to specify a path,
you can use options(sandpaper.handout = "/path/to/handout.R")
to save the
handout to a specific path.
Usage
build_handout(path = ".", out = getOption("sandpaper.handout", NULL))