Change slsn module to use blackbody_cutoff
Change slsn module to use blackbody_cutoff

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