Example of using `knitrBootstrap` on a package vignette

[Leonardo Collado-Torres]

Hi,

For those interested, here is an example of using knitrBootstrap to build the vignette of a package.

https://github.com/lcolladotor/derfinderHelper/blob/master/vignettes/Makefile

I made it so it works with either the current CRAN or the current GitHub version. In my case, I prefer the GitHub version but I need it to run with CRAN-only versions. This is due to how Bioconductor builds/checks the packages (no GitHub packages are allowed).

On the particular example, I am using a 'fake' and 'real' vignette directory. This is just to keep R CMD check --no-build-vignettes under 5 minutes as required by Bioconductor while also building the real vignette when necessary (you can view it here).

You will note that the makefile uses library(methods). The reason is described at cboettig/knitcitations#52

Cheers,
Leo