swc-windows-installer.py: Look for an R bin directory

swc-windows-installer.py: Look for an R bin directory

On Thu, May 15, 2014 at 08:07:19PM -0700, Ethan White wrote:
> Problem: R is not added to the Windows' path when it is
> installed. This means that any workshops that use R from the command
> line will run into problems (as we did at the first Data Carpentry
> workshop).
>
> Solution: Add R to the path using our Windows' installer.
>
> Challenges: Just to make @wking's life exciting, R's path varies
> depending on the version. The standard path is `C:\Program
> Files\R\R-x.x.x\bin\` where `x.x.x` is the version number of the
> installed version of R.