[Rd] HTML vignette browser

[Deepayan Sarkar]

Hi,

this is tangentially related to the recent discussion on vignettes.
vignette() currently produces a listing of available vignettes, but
these are not clickable. Since R has a browseURL() function, it seems
natural to have a version that produces HTML with clickable links.
Here's an attempt at that:

source("http://dsarkar.fhcrc.org/R/vignette-browser.R")
browseVignettes()
browseVignettes(package = "grid")

etc. Perhaps some variant of this could be added to R.

Comments welcome.

-Deepayan