Changes to TunnelIt between r5 and r17

''Ethernet tunnels with a netcat-like tool'' --> '''Ethernet tunnels with a netcat-like tool'''
'''Security Note:''' No authentication of any type is performed, it is assumed that you take care of this at lower layers (firewall, physical access, etc).  This tool is intentionally simple.
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How to use it:
   * Host A (listener):
   ** `host-A# tunnelit-p2p -l` -->    ** `hostA# tunnelit-p2p -l`
    ** `host-A# ifconfig tap0 10.72.51.1 netmask 255.255.255.0 broadcast 10.72.51.255` -->    ** `hostA# ifconfig tap0 10.72.51.1 netmask 255.255.255.0 broadcast 10.72.51.255`
    * Host B (connector):
   ** `host-B# tunnelit-p2p -H host-A` -->    ** `hostB# tunnelit-p2p -H hostA`
    ** `host-B# ifconfig tap0 10.72.51.2 netmask 255.255.255.0 broadcast 10.72.51.255` -->    ** `hostB# ifconfig tap0 10.72.51.2 netmask 255.255.255.0 broadcast 10.72.51.255`
Other options:
Usage: tunnelit-p2p [-VFhluo] [-p port] [-H host] [-d devname] [-f tunpath]
                     [-t keepalive]
   -V            Print version and exit -->     -V              Print version and exit
    -F            Run in foreground (default is to background) -->     -F              Run in foreground (default is to background)
    -h            Print this help and exit -->     -h              Print this help and exit
    -l            Listen (default is connect) -->     -l              Listen (default is connect)
    -u            UDP mode -->     -u              UDP mode (implies "-o")
    -o            Only allow one client to connect at a time. -->     -o              Only allow one client to connect at a time.
    -H <host>     Connect to host, required if "-l" not specified -->     -H <host>       Connect to host, required if "-l" not specified
    -d <devname>  TUN/TAP device name -->     -d <devname>    TUN/TAP device name (i.e., "tap0")
    -f <tunpath>  Path to kernel TUN interface (default: /dev/net/tun)
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    -f <tunpath>    Path to kernel TUN interface (i.e., "/dev/net/tun")
    -t <keepalive>  Specify how frequently to send keepalive packets, in
                    seconds (default: 900)
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Download:
    * http://www.rkeene.org/devel/tunnelit-0.0.0.1495.tar.gz -->     * http://www.rkeene.org/devel/tunnelit-0.0.1.1514.tar.gz
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Screenshots:
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[http://www.rkeene.org/projects/info/resources/projects/tunnelit/tunnelit-p2p-1.png]

Legend

     Only in r5
     Only in r17
     -->      Modified slightly between r5 and r17