Updates to calibration model

[evan-greenbrg]

1. Fixes prior_rcc input path. Prior file is a .mat file with keys, mean, cov, bounds, scale (optional)
2. Switches to analytic partials in the jacobian construction for EOF and RCC statevector terms. Check my work here:
   dmeas/dEOFscaler is linear w.r.t. the fixed EOF vector
   dmeas/dRCC is linear w.r.t. the radiance (resampled to measurement wavelengths)
3. How does the retrieved RCC vector relate to the Uncertainty due to radiometric calibration we include in Seps