IMPORTANT: code has been updated a lot and thoroughly tested for the HM-Bethe case.
Sparse matrix structure introduced in the code and tested. Improve speed and
memory management.
A version (soon to be pre-compiled) using direct Hamiltonian product H*v, so not
storing the matrix itself, is written and tested but appears to be significantly
slower.
GETGF got a major improvement, with subdivision in routines building the GF, both for
the full and lanczos case.
DIAG/VARS_GLOBAL got several improvements concerning the maps and arrays used to
go forth and back the total Hilbert space. Although this solution is still unsatisfactory
on a general ground, a look-up table is very much desirable at this point, modifications
improve memory usage.
BATH is now randomly guessed.
Nimp-->Norb, ready to go multi-band that is easy now.
N-->Ntot to avoid problems in variables naming.
Merge branch 'devel'

Conflicts:
	Makefile