Promises support for http object

The http object now returns promises (still runs callbacks if passed). This allows:

  http.get('http://www.foo.com').then(function (response) {
    // ... Do stuff
    return something;
  }).then(function (something) {
    // ... More stuff
  });

Remove old dependencies

Tough-cookie and Request are no longer used

Updated docs and dependencies

Merge pull request #21 from Narzerus/development

Development