Fix detail in hubbard_I solver

  modified:   pytriqs/solvers/hubbard_I/solver_base.py
Write multiplications by matrices for gf's

  modified:   pytriqs/base/gf/local/gf_generic.py
Put new Green's functions in dft part

  modified:   pytriqs/dft/sumk_lda.py
  modified:   pytriqs/dft/sumk_lda_tools.py
  modified:   pytriqs/dft/symmetry.py