doc: minor fix

mnl_attr_ok(): fix return value type
mnl_attr_put_u8(): remove unused param - len
mnl_attr_put_u8_check(): remove unused param - len
mnl_nlmsg_ok(): fix return value type
mnl_nlmsg_batch_stop(): not return batch size, but release it

Signed-off-by: Ken-ichirou MATSUZAWA <chamas@h4.dion.ne.jp>
Signed-off-by: Florian Westphal <fw@strlen.de>
headers: update netlink.h to 3.10

To prepare adding mmap socket functions.

Signed-off-by: Ken-ichirou MATSUZAWA <chamas@h4.dion.ne.jp>
socket: memory mapped netlink I/O support

referencing the nl-mmap branch,
commit: c090ef012f7c373e128c93068e6b77d7379a93a8

Signed-off-by: Ken-ichirou MATSUZAWA <chamas@h4.dion.ne.jp>
examples: add for mmap

some of existing.

Signed-off-by: Ken-ichirou MATSUZAWA <chamas@h4.dion.ne.jp>
examples: add nfct stats and veth examples

Signed-off-by: Ken-ichirou MATSUZAWA <chamas@h4.dion.ne.jp>