BHZ_ED driver under testing.
Some minor modification to the code, mainly inherent reading and using Hloc.

Tested ED_LDA for multi-bands. using it for PAM/tddPAM calculations.
bug fixing: the Kanamori form of the Hamiltonian was
incompatible with Hartree shifted chemical potential (mu=0 for half-filling,
corresponding to n--> n-1/2). fixed by adding proper shifts if hfmode=T.

bug fixing: the plot routine in chi2_irred printed out last orbital function in
all cases, fixed by re-reading input function.

ed_bhz: code reverted to irreducible bath for testing.
If Rashba coupling is not included there are no mixed GF, or these are zero
making the fit procedure kind of hard.
bug fix: error in evaluation of the moment-moment  correlation function
<m_z^a.m_z^b> in the code. The nup^a, ndw^a variables were initialized
inside the loop over the orbitals, so m_z^b=nup^b-ndw^b was not
available at evaluation time. fixed, thanks G.Giovannetti.