Wrap code in README.md in code blocks

[ramnathv]

Just a simple cosmetic fix, wrapping up code blocks in README.md so that they are syntax highlighted by github.

[ramnathv]

I have created a .gitignore with a few file patterns that you don't want to commit to github. Your .Rhistory in particular, since it logs everything from your R session and hence might information you don't want shared. I have also added .cache which is the default cache directory for knitr, since it can bloat the size of the repo.

Note that the .gitignore patterns will kick in only for the newly commited files. You will have to manually delete them for the files already commited and use git rm --cache to purge them from the repository.