README: Reformat to use headings

# Work In Progress, do not merge

Looking to reformat the readme so the options use heading that can be linked to directly.
I only fully converted the first few options, but I wanted to see if you're OK with the format before I try doing it for all the options.

You can see how it would look rendered here https://github.com/nschonni/node-jscs/blob/98fee00cfe1d499e60c4f5eac448dfbbde1e70c9/README.md