sd: use description field instead of longname parameter
sd: use description field instead of longname parameter

This gets the name of the playlist node for a playlist SD from the
SD module intance rather than from a configuration chain. The latter
was a rather ugly hack, and did not work with the command line (-S).

It also fixes localization of the name.

xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc