docs: function signalFromEvent (target, event) {
    return new QuickSignal(function (subscriber) {
      var handler = function (e) {
        subscriber(e);
      };
      var el = angular.element(target);
      event.split(' ').map(function (e) {
        el[0].addEventListener(e, handler, true);
      });
      subscriber.$dispose = function () {
        event.split(' ').map(function (e) {
          el[0].removeEventListener(e, handler, true);
        });
      };
    });
  }