Fix interface with OCC

[peterspackman]

Since the change in defaults in occ to write out json wavefunction files, most of the functionality working with the old CE code and tonto is broken.

This includes:

• Interaction energies calculated via tonto
• Wavefunction properties

This could be addressed via adding a flag to occ to write out .fchk files, though that will cause issues when calculating with ECPs. That's likely not a major problem given tonto and the previous code couldn't deal with ECPs from e.g. Gaussian09 either.