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.
I am not sure we need the '/' here (we are downloading to the current directory from what I can see). Also two spaces indent should be fine inside the `if` block.