highlighted bean image links to content (bean page)

unless there are legacy reasons why this is it is probably not the ideal behaviour. the link could just be removed but having the image link to the path entered in the linkfield might be more practical. I could just use [my own bean type](https://drupal.org/sandbox/discipolo/1972316) if there is a reason highlighted works this way, otherwise this pullrequest replaces the display formatter for highlighted image field with https://drupal.org/project/image_link_formatter