lcfit.mandelagol_fit_magseries: minor cleanup and some FIXMEs
lcfit.mandelagol_fit_magseries: minor cleanup and some FIXMEs

lgbouma/astrobase,lgbouma/astrobase,waqasbhatti/astrobase,lgbouma/astrobase,waqasbhatti/astrobase,waqasbhatti/astrobase