Full and privileged xtb integration?

[ghutchis]

@matterhorn103

Will readProperties replace the current set of properties with the new ones or just add the differences? I.e. would an extant set of vibrations be deleted by passing only orbitals?

At the moment, it replaces the properties. Safely merging properties is a bit trickier.

In the meantime, I can verify that your Frequencies and Orbitals script do work with the patch.