[Feature Request] Add where method to find value location

querying objects in locker should query both session, and local unless specified. If I say locker.has('user') I would expect that to return true if there is an object called 'user' in either the local or session storage.

Example use case:

app.controller('LoginCtrl', [
  '$scope', 'locker', function($scope, locker) {
    $scope.email = '';
    $scope.password = '';
    $scope.rememberMe = false;
    $scope.signIn = void 0;
    $scope.user = {
      email: '',
      password: ''
    };
    $scope.rememberMe = false;
    return $scope.signIn = function() {
      if ($scope.rememberMe) {
        return locker.driver('local').put('user', $scope.user);
      } else {
        return locker.driver('session').put('user', $scope.user);
      }
    };
  }
]);

Here I allow the user to define which locker they use. Specifying driver on locker.put makes sense, but now later through out my application I either need to create a $rootScope variable to tell me which locker to use or I need to do this all over the place:

if (locker.driver('local').has('user')) {
      return locker.driver('local').get('user');
    } else {
      return locker.get('user');
}

Ideally both locker.has and locker.get would query both lockers, unless I specifically say locker.driver('local').has or locker.driver('local').get