update gw tutorial
update gw tutorial

alexmoratalla/yambopy,henriquemiranda/yambo-py,alexandremorlet/yambopy,alexandremorlet/yambopy,alexmoratalla/yambopy,henriquemiranda/yambopy,henriquemiranda/yambo-py,alexmoratalla/yambo-py,alexmoratalla/yambo-py,palful/yambopy,henriquemiranda/yambopy,palful/yambopy