Tesserae vertices and arcs should be written to file

[robertodr]

Tesserae vertices and arcs are currently not written to file. If a restart on the cavity is done with a non isotropic solvent this would result in a failure when calculating the diagonal elements of the boundary integral operators.
We need to decide if it's necessary to write vertices and arcs to file or just crash with an informative message when the combination restarted cavity/non isotropic solvent is chosen.