ocarina: Hide empty playlists

If the playlist size == 0, then we don't need to show it.  This hides
the banned list when it doesn't contain any songs.

Signed-off-by: Bryan Schumaker <bjschuma@gmail.com>

ocarina/playlist/insert.cpp

@@ -38,6 +38,10 @@ namespace ocarina
 		gtk_widget_thaw_child_notify(treeview);
 		gtk_tree_view_set_model(GTK_TREE_VIEW(treeview), filter);
 		set_label_text();
+		if (playlist->get_size() == 0)
+			gtk_widget_hide(box);
+		else
+			gtk_widget_show(box);
 	}
 
 	void Playlist::remove_index(unsigned int index)