SparkR Quick-Start and IDE Setup

Includes .md files for a SparkR quick-start tutorial as well as as a short guide to getting Rstudio set up and working with SparkR on the Cloudera VM.

In addition, this commit includes a shell script that handles the Rstudio set-up.
1. You're correct.  It's currently doing essentially the same thing, but that's relying heavily on the assumption that the user will do everything exactly according to plan (aka a silly assumption on my part).

2. I'll talk to Dr. Dan about this one and see what he thinks.  I think it may make sense to roll this into the install script, but then update this .md file to be a more general discussion of getting Rstudio and SparkR set up regardless of whether or not you're using the VM.  That way VM users get it automatically, but there's also some additional documentation in the WIki about pulling SparkR into any IDE setup using the .Rprofile hack.  How's that sound?