redundant brackets in README.md

[cuteason]

The redundant brackets exist in the example given in the [What Makes node-windows Services Unique?] section.

var svc = new Service({
  name:'Hello World',
  description: 'The nodejs.org example web server.',
  script: 'C:\\path\\to\\helloworld.js'), <- There it is.
  wait: 2,
  grow: .5
});