python3: fix invalid indentication
examples: update
attr: make attr_put() accept netlink.UStructure
header: add for examples/nf-log

just for showing payload length.
It might be going to be discard.
API: change method name

Header.attr_parse() to Header.parse()
and change optional param name of Header.fprint
examples: update

follow changing method name, attr_parse() to parse()
and some cleanups
examples: add nf-queue
memo: fix typo
examples: add and update