netsniff-ng 0.5.9-rc4

1. Restore tpacket v2 capturing functionality. Thanks to Mike Reeves for his help with testing these changes. By Tobias Klauser.
2. Add option --no-sock-mem to trafgen to disable adjusting socket memory (analogous to the iexisting netsniff-ng option of the same name). By Jesper Dangaard Brouer.
3. Check for correct linktype in netlink dissector. By Daniel Borkmann.
4. Add build flag for sparse static checking and fix some of the reported warnings. By Tobias Klauser.