Some additional models for astromodels. At the moment:

Absori (https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/node232.html; Magdziarz & Zdziarski (1995, MNRAS 273, 837))
Integrated Absori (xsigmaabs for IGM: https://var.sron.nl/SPEX-doc/manualv3.05/manualse85.html; Steenbrugge et al. (2003))

Depends on astromodels (https://github.com/threeML/astromodels). Models are taken from XSPEC code (https://heasarc.gsfc.nasa.gov/xanadu/xspec/) and rewritten for python.
