This frame is intended for URL [URL] links concerning the audio file
in a similar way to the other "W"-frames. The frame body consists
of a description of the string, represented as a terminated string,
followed by the actual URL. The URL is always encoded with ISO-8859-1
[ISO-8859-1]. There may be more than one "WXXX" frame in each tag,
but only one with the same description.
<Header for 'User defined URL link frame', ID: "WXXX">
Text encoding $xx
Description <text string according to encoding> $00 (00)
URL <text string>
@author Eric Farng
@version $Revision: 1.4 $