Add blog post on the novice R materials and discuss future plans.

Sorry for the confusion. This PR replaces #641. I've copy-pasted my original message below:

This blog post has two primary purposes:

* Announce that the novice R materials have been translated and are now available on the SWC website.
* Provide some direction for future lesson development.

I'd appreciate all feedback. Especially from @eddelbuettel and @gavinsimpson, since I quote from your recent posts on r-discuss, @tracykteal, since I discuss Data Carpentry, @sritchie73, since I use your blog post as an example, and @dhaine. Thanks!
I would shorten this paragraph to, "We set out six months ago to create a set of lessons that would be developed, maintained, and used by everyone in the Software Carpentry community who is teaching R. Having built these lessons, I now question whether that was the right goal."