removed ids_data, updated link generator, updated tests

Hi Roman,
Here is the update to see the arxiv links.  I had to update the json for results_render_widget.spec.js to not have ids_data and to have the new links_data structure and it somehow affected the pagination test, so the test that begins
      it("should listen to START_SEARCH and automatically request and render data", function (done) {

now has:                      expect(widget.collection.length).to.eql(20);
whereas it used to be: expect(widget.collection.length).to.eql(10);

Do you have any idea why this might be?

Otherwise I think everything is fine.