fix #1415
fix #1415

Songs from netease cloud music playlist will have a prefix indicates
their order in the list.

zmwangx/you-get,cnbeining/you-get,xyuanmu/you-get,qzane/you-get,cnbeining/you-get,qzane/you-get,zmwangx/you-get,xyuanmu/you-get