PHP notice in multi-checkbox-control

```
[08-May-2014 16:06:55 UTC] PHP Notice:  Undefined index: default in /srv/www/largo.dev/wp-content/themes/largo/inc/customizer/class-largo-wp-customize-multi-checkbox-control.php on line 11
[08-May-2014 16:06:55 UTC] PHP Notice:  Trying to get property of non-object in /srv/www/largo.dev/wp-content/themes/largo/inc/customizer/class-largo-wp-customize-multi-checkbox-control.php on line 11
```