[views] implement a custom json error view If the client asked for ``(e)jsonexport`` view, answer him with a json response rather than an error formatted in a big HTML blob. add a custom _requested_vid predicate. In cw 3.21, it will be deprecated in favor of ``match_form_params(vid=('jsonexport', 'ejsonexport'))``

$(document).ready(function() {

  module("air");

  test("test 1", function() {
      equals(2, 4);
  });

  test("test 2", function() {
      equals('', '45');
      equals('1024', '32');
  });

  module("able");
  test("test 3", function() {
      same(1, 1);
  });
});