Minor addition of some variables in SetupFromSpglib()

[ManexAlkorta]

Addition to support the new function get_free_energy_hessian_dev() in python-sscha

[mesonepigreco]

Hi Manex,
Can you briefly explain what the new variables are used for and what their expected sizes are? This in cellconstructor should be a really trivial addition; however, we must be careful, as they are allocated a lot inside the sscha code, and I see they are a 3-rank tensor (I assume symmetries X nat X 3, am I right? Is the structure in the primitive or in the supercell? In this case, it should be safe for memory, as it is likely the same memory as one configuration of the ensemble per symmetry, and usually we have a much larger number of configurations than symmetries)

[mesonepigreco]

@ManexAlkorta It seems there is a failure in one of the test, can you check?