fix ordering of gradient items in evaluate_in_rc()
fix ordering of gradient items in evaluate_in_rc()

- ordering corresponds to (n_coor, n_components, dim) as described in
  Field.evaluate_at() docstring

lokik/sfepy,BubuLK/sfepy,rc/sfepy,rc/sfepy,lokik/sfepy,sfepy/sfepy,rc/sfepy,BubuLK/sfepy,vlukes/sfepy,sfepy/sfepy,lokik/sfepy,vlukes/sfepy,sfepy/sfepy,lokik/sfepy,vlukes/sfepy,BubuLK/sfepy