spectrum viewer: show photometry points

In the 3rd HDU of pfsObject, there is a list of fiberMags.  Let's have a button somewhere in the spectrum viewer to display the photometry points on top of the observed spectrum.  In this v2.5 simulation, the photometry does not agree with the spectrum in most filters, except for the i-band, in which the broad-band photometry and spectral flux agrees.  We were too lazy to simulate various spectral shapes, and we assume only a few template spectra.  These template spectra were scaled to match with the i-band photometry.