ENH: added Z filter
ENH: added Z filter

villrv/MOSFiT,guillochon/MOSFiT,guillochon/FriendlyFit,guillochon/MOSFiT,guillochon/MOSFiT,bmockler/MOSFiT,mnicholl/MOSFiT,mnicholl/MOSFiT,bmockler/MOSFiT,mnicholl/MOSFiT,villrv/MOSFiT