Helper class for custom RSS handling
$_id_missing :
$_local_guid :
get_title()
get_description( $description_only = false)
get_content( $content_only = false)
get_link( $key, $rel = 'alternate')
get_id( $hash = false, $fn = 'md5')
get_local_guid()
set_local_guid( $guid)
_decode( $string)