MAINT: Cleanup refdata, fitting, and core.eqresult #135
These modules appear to be dead code and unused and are removed.
refdata will be released in ESPEI with ESPEI version 0.3.1
I've replaced the code in the refdata module with an import error saying that it has been moved to ESPEI. @richardotis do you think this is necessary? Should we include a date that the pycalphad.refdata module will be removed from pycalphad, e.g. pycalphad 0.7?