Adding script mode code for describing global scaling in I(Q)

[qzhang234]

One very useful analysis in SAXS I(Q) is the identification of a global scaling. During liquid-liquid phase separations, the system may evolve in a way where the characteristic length scale increases, but the statistics of the spatial configuration remains the same. This is a hall-mark feature for spinodal decomposition (see screenshot 1, from PRL 126, 138004 (2021)). Furthermore, fitting the master curve will unravel more information regarding the physical nature of the phase transition (see screenshot 2, from PRL 125, 125504 [2020]).

The request has two components:

1. Please add the feature that identifies the master curve from a group of SAXS 1D results, and output both the master curve and the scaling coefficients for each SAXS 1D plot.
2. Please add the feature that fits the master curve, starting with Eq. 1 in the 2020 PRL.

Thank you!