api: no need len param
examples: update

and fix poll exception handling
errno: clear before raise OSError
socket: fix wrong len param

and typo
doc: update require

just listing
examples: fix value passing to getsockobj

and IPv6 printing
test: update errno handling
errno: avoid KeyError

in case of no errno have set
api: add getsockop_as
test: add for socket
examples: remove l4 info

created too many paths
examples: move graphite example