Feature: playlist history for ICY based streams.

This patch adds support for history for ICY based streams.
Of cause this has the same limits for metedata as ICY has.

See: #766

src/format_mp3.c

@@ -181,6 +181,7 @@ static void filter_shoutcast_metadata (source_t *source, char *metadata, unsigne
                 stats_event_conv (source->mount, "title", p, source->format->charset);
                 yp_touch (source->mount);
                 free (p);
+                playlist_push_track(source->history, &source->format->vc);
             }
         } while (0);
     }

src/playlist.c

@@ -141,6 +141,11 @@ int          playlist_push_track(playlist_t *playlist, vorbis_comment *vc)
         track->creator = __query_vc(vc, "ARTIST");
         track->album = __query_vc(vc, "ALBUM");
         track->trackNum = __query_vc(vc, "TRACKNUMBER");
+
+        if (!track->title && !track->creator && !track->album && !track->trackNum) {
+            /* no useful meta data has been found. try ICY style meta data */
+            track->title = __query_vc(vc, "X_ICY_TITLE");
+        }
     }
 
     return 0;