Class attributes should be an array, not a string

Line 1239 user_badges.module sets the class attributes as a string - it should be an array, i.e.:

'attributes' => array('class' => array($badge->class)),

This is the same issue as Media module: #1722146: Media filter is using string instead of array for the class attribute

And as discussed here: http://drupal.org/node/1711746#comment-6383342