Thermo estimator fix to allow solvation corrections

This is a pull request related to #308.
I made several test cases by comparing the thermo obtained with the thermoEstimator and  the thermo obtained during a "regular generation". It gives me the same value for liquid phase estimation.
I also checked that gas phase estimation are still working, which is true.
If a species is matching a library the estimation is still correct.

It seems ready to merge for me.