Ncat: Implement idle timeout option for listen mode

This patch implements "-i" (idle timeout) option for listen mode.

Signed-off-by: Tomas Hozza <thozza@redhat.com>
Ncat: Add tests for idle timeout in listen mode

This patch adds tests for idle timeout in listen mode
for all supported protocols. It also modifies existing
test for idle time in connection mode to test the option
for all supported protocols.

Signed-off-by: Tomas Hozza <thozza@redhat.com>
CHANGELOG for -i in listen mode.

http://seclists.org/nmap-dev/2013/q2/403