Initial import.

This is pynids 0.6.1 taken from Jon Oberheide.

http://jon.oberheide.org/pynids/
Add time tracking.

Added tracking of per-flow last-packet-timestamp to allow the option of timing
out flows. This is enabled by setting the tcp_flow_timeout nids parameter to a
value greater than zero. Set tcp_flow_timeout to the number of seconds after
which the flow will timeout. Note that the timeout is only checked when a new
SYN packet is seen from the same TCP/IP tuple.

Thanks to an anonymous contributor for this patch.