UPDATE [CODE RESHUFFLED]:
we update the wrap of ED solver by exploding the main ed_solve_impurity routine, which
was performing all the tasks: i. solve ed problem, ii. get local GF, iii. get
updated Weiss field and fit new bath, into three new different class of routines (overloading
the different cases).
We tested the new version of the code with respect to the old one and got numerically identical
results (tested with diff).
UPDATE [implementation of symmetries]:
we introduced a 'rudimentary' implementation of the symmetries
of the real space lattice.
The subroutine GET_INDEPENDENT_SITES contained in RDMFT_AUX_FUNX
searches for all independent sites with respect to the
symmetry operations definened by the user inside the driver.
Maps between full and reduced lattices are built.

TESTED for the stripe geometry with modulated interaction in the cases
       -no symmetries
       -Uperiod translation symmetry
       -Uperiod translation + x-Axis reflection symmetry

Minor changes in the tight-binding hamiltonian.
We introduce the possibility of defining periodic-boundary-conditions
in the X and Y direction separately.
CODE UPDATED: RDMFT code interfaced with the last version of ED_SOLVER
     	      in which we removed a bug in the printing routine
	      'print_imp_gf'
	      (see commit 37b19635427f366f9fcaab4caac26a8c1919759f in ED_devel
	      for details).