Replace options() with withr::with_options() throughout

[jbullock35]

https://stackoverflow.com/questions/65466324/why-are-sapply-and-options-undesirable

See zzz.R in my package.

Perhaps also replace this code from latexTablePDF() with an option:

  # CHECK FOR PDFLATEX
  # This is a time-consuming operation. So if we find pdflatex the first time,  
  # we create the ".pdflatex_found" variable in the user's environment. In 
  # future runs of latexTablePDF(), the check aborts if ".pdflatex_found" 
  # exists.  [2020 01 01]
  if (writePDF && !exists(".pdflatex_found")) {
    if (!nzchar(Sys.which("pdflatex")))  {
      stop("pdflatex doesn't seem to be on your path. A PDF file can't be created.")
    }
    else {
      assign(".pdflatex_found", TRUE, envir = parent.frame())
    }
  }