Feature request: Combined read_html/write_html function

[richierocks]

If you are scraping a website, it is good practise to download the page once and store a copy, so you don't have to keep re-downloading it.

That means that it is easy to end up with lots of code like

page <- read_html(url)
write_html(page, "somefile.html")

It seems like it would be useful to have a single function (save_html() perhaps) to do both operations.

The dumbest implementation is something like this:

save_html <- function(x, file) {
  page <- read_html(x)
  message("Writing to ", force(file))
  write_html(page, file)
  invisible(page)
}

It needs a bit of fleshing out to deal with ... args to read_html() and write_html(), to it would be nice to have a default filename generated from the URL.