#2514: broken support for piecewise polytropes in IllinoisGRMHD

Comment (by Zach Etienne):

The main documentation (the IllinoisGRMHD paper https://arxiv.org/pdf/1501.07276.pdf ) says:

“… the current version supports only single gamma-law EOSs…”

Full support for the “hybrid equation of state” (of which piecewise polytrope is a limiting case) was incorporated into the NRPy+ version of IllinoisGRMHD, which is rather pedagogically documented in many Jupyter notebooks:
https://nbviewer.jupyter.org/github/zachetienne/nrpytutorial/tree/master/IllinoisGRMHD/doc/

We proposed this version for inclusion in the Toolkit but it was rejected due to very minor backwards incompatibility.