HGH and heavy elements

Description

Sometimes, the last point of the pseudowavefunctions are non-zero (bug?) and this was breaking the routine ps_check_bound. This MR addresses this problem.

Moreover, the parameters of the HGH logarithmic grid were hardcoded, which was leading to too coarse grid for heavy elements. The parameters are now obtained based on the nuclear charge, which give much better results.

In the attached document, one sees the pseudo-atomic wavefunction before and after the change: Dy_4f.pdf Now, the 4f orbitals of Dy are correctly found to be bound states.