when I activate your plugin it interferes with my adding featured images to my posts. I can upload the image, but i cant set it.
The problem comes from enqueing the media_upload_script on line 46; add_action('admin_enqueue_scripts', array($this, 'media_upload_scripts'));
Also, I get the warning 'Notice: get_usermeta is deprecated since version 3.0! Use get_user_meta() instead.'.