Implement create veth

Docker-DCO-1.1-Signed-off-by: Guillaume J. Charmes <guillaume.charmes@docker.com> (github: creack)
Merge remote-tracking branch 'mike/add-netlink-functions' into implement_create_veth

Conflicts:
	pkg/netlink/netlink_linux.go

Docker-DCO-1.1-Signed-off-by: Guillaume J. Charmes <guillaume.charmes@docker.com> (github: creack)
Merge pull request #7 from creack/implement_create_veth

Implement create veth