set up vignettes / move wiki to vignettes

[maxheld83]

It seems to me that vignettes may be a superior format / way of doing extended documentation of the kind we've currently been doing on the wiki.

For more information, see

• Hadley's book chapter: http://r-pkgs.had.co.nz/vignettes.html
• as an example, Hadley's vignettes for dplyr https://cran.r-project.org/web/packages/dplyr/

Advantages would be:

• Have this kind of extended documentation inside the repo, so it goes along with changes in the program
• Available in various R clients, including RStudio, right in the terminal
• Nice formatting options (via rmarkdown)
• Literate programming approach to extended documentation (via rmarkdown and knitr)
• Possibility to publish papers out of vignettes (to R Journal or Journal of Statistical Software or OS etc.)

Might be a gradual move, but I think for the future, this might be the way to go.

[maxheld83]

incidentally, we could keep the resulting rendered *.mds in the Wiki, too – but that would mean an extra step and things would be (confusingly) available in two separate places.

I'd suggest to use the wiki more for strictly "about"/"meta" kind of information, like how to install the program, etc.