angular.d.ts IDocumentService extends IAugmentedJQuery

Updated `IDocumentService` to extend `IAugmentedJQuery` rather than `Document`. As per [the API](http://docs.angularjs.org/api/ng.$document) it provides:

> A jQuery or jqLite wrapper for the browser's window.document object.

This is raised [in issue 1357](https://github.com/borisyankov/DefinitelyTyped/issues/1357).