Provide pinp.cls if not present

[eddelbuettel]

I am a little non-plus'ed that adding pinp as the vignette driver leads to two extra files.

I already figured out how to get rid of one---we can just include the content of the Bibtex-rendered .blg file directly in the source Rmd, which frees us from adding a foo.bib file. Down one. (Of course, you want it while you still edit the document. Once done, and included as a more static vignette you do not and the extra file is line noise.)

And I realized that we have a code hook to just copy in pinp.cls from the pinp skeleton directory if it is not present in the current working directory---and tada we also get rid of pinp.cls.

Good idea? Methinks it is.

[coatless]

Yeah, I was actually toying around with this in: illinois-r/uiucthemes#4

Basically, the pinp function can call system.file() and create the appropriate linking path. Though, I think some of my earlier tests ran afoul with Windows and spaces in the Program Files path. I'll need to set up a parallel session to test now as the windows box is fried...

[eddelbuettel]

It is trivial, and I will commit it:

    if (!file.exists("pinp.cls"))
        file.copy(system.file("rmarkdown", "templates", "pdf", "skeleton", "pinp.cls",
                              package="pinp"),
                  ".")

Has the advantage of copyinig a current pinp.cls in too (if you do a quick rm pre-rendering) when you are making changes.