ENH: refstates: Rename SGTE91 to SGTE91Stable. Add additional SGTE91 lattice stability data using the SGTE91 name.
ENH: refstates: Rename SGTE91 to SGTE91Stable. Add additional SGTE91 lattice stability data using the SGTE91 name.

tkphd/pycalphad,tkphd/pycalphad,tkphd/pycalphad