Allow specifying a "dataField" to extract JSON

This is needed when dealing with JSON APIs that always return a root
object, even for Arrays. Similarly, it's needed if the API returns a
root object because it also needs to return some "meta" data, like
pagination.

e.g.,
{
  "meta": {
    "page": 1,
    "totalPages": 42
  },
  "results": [
    {
      // The actual search result object
      "name": "Superman",
      "description": "The Man of Steel"
    },
    //...
  ]

}
Use extractValue to get title and description
Clean up whitespace
Update example app with new code
Remove unused CSS and JS files

The files used by index.html live in example/css/ and
example/js/app/directives/, respectively.
Merge pull request #2 from stevenharman/declare_remote_data_field

Declare remote data field