Set color terms to 0 for 0.4m telescopes and tfn 1m

[abostroem]

Right now the 0.4m SBIGs get the color terms measured on the 1m SBIG telescopes at their respective sites and all SBIGs at tfn get a color term which is an average of all of the SBIG sites. This is wrong. Without the human power to derive these color terms, we should modify the logic to set these to 0 rather than apply incorrect color corrections.

For reference for whoever is making this code modification:
fs and em = 2m Spectral
fa and fl = 1m Sinistro (these are stable across different sites)
ep = 2m MUSCAT
all site color terms are for 1m SBIGs (see Valenti et al 2016 appendix). SBIGs are not as stable as the Sinistros so we expect each camera to be different