can now recover RV, EBV from the artifically reddened 11fe with chi/dof = 1
small changes to go along with photom_vs_spectral3D.py
added nearest_spectra(); instead of interpolating, we now look for the nearest 11fe phase that matches a 12cu phase.  and we only use SNF data.  We can match well 11 of the 12cu phases.