Completed one composition parameter estimation

tests/test_reeps.py

@@ -7,4 +7,12 @@ import json
 with open('one_comp_settings.txt') as file:
     testing_params = json.load(file)
 beaker = REEPS(**testing_params)
-print(beaker.get_in_moles()['Nd+++'])
+
+minimizer_kwargs = {"method": 'SLSQP',
+                    "bounds": [(1e-1, 1e1)],
+                    "constraints": (),
+                    "options": {'disp': True, 'maxiter': 1000, 'ftol': 1e-6}}
+est_enthalpy = beaker.fit(minimizer_kwargs)
+print(est_enthalpy)
+beaker.update_xml(est_enthalpy)
+beaker.parity_plot()