IR Shifted-peak fitting

This is a set of routines designed to fit temperature-dependent amide I infrared spectra of proteins and peptides. It has been shown that these peaks are temperature-dependent. The data is fit to a sum of Gaussian peaks, with center position and width of each peak assumed to shift linearly with temperature. In addition, the model allows an equilibrium between peaks, so that each peak may (optionally) increase or decrease in amplitude with temperature. The change in amplitude with temperature is modeled as a two-state equilibrium.