Turn off sort indicators for playlist

Fixes #511

src/playlist/playlistview.cpp

@@ -353,6 +353,8 @@ void PlaylistView::LoadGeometry() {
     header_->ShowSection(Playlist::Column_Title);
   }
 
+  header_->setSortIndicatorShown(false);
+
 }
 
 void PlaylistView::SaveGeometry() {