Move -L flag doc to manpage

doc/NEW_FEATURES.txt

@@ -3,19 +3,3 @@ Between 2.0.x and 2.1.x
 
 * Better ming Windows build support.
 * Added -E flag to allow multicast ethernet traffic.
-
-* Added -L flag to allow set TTL for registration packet.
-This is an advanced flag to make sure that the registration packet is dropped immediately when it goes out of local nat
-so that it will not trigger some firewall behavior on target peer. Actually, the registration packet is only expected to
-make local nat UDP hole and is not expected to reach the target peer, see https://tools.ietf.org/html/rfc5389.
-To achieve this, the flag should be set as nat level + 1. For example, if we have 2 layer nat in local, we should set
--L 3.
-Usually we know exactly how much nat layers in local.
-If we are not sure how much nat layers in local, we can use traceroute on Linux to check. Following example shows a local
-single layer nat because on second jump it shows a public ip address. In this case it should set -L 2.
-$ /usr/sbin/traceroute -w1 8.8.8.8
-traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 60 byte packets
- 1  192.168.3.1 (192.168.3.1)  0.464 ms  0.587 ms  0.719 ms
- 2  112.65.17.217 (112.65.17.217)  5.269 ms  7.031 ms  8.666 ms
-
-But this method is not always work due to various local network device policy.

edge.8

@@ -4,7 +4,7 @@ edge \- n2n edge node daemon
 .SH SYNOPSIS
 .B edge
 [\-d <tun device>] \-a <tun IP address> \-c <community> {\-k <encrypt key>|\-K <keyfile>} 
-[\-s <netmask>] \-l <supernode host:port> 
+[\-s <netmask>] \-l <supernode host:port> [\-L <reg_ttl>]
 [\-p <local port>] [\-u <UID>] [\-g <GID>] [-f] [\-m <MAC address>] [\-r] [\-v]
 .SH DESCRIPTION
 N2N is a peer-to-peer VPN system. Edge is the edge node daemon for n2n which
@@ -111,6 +111,26 @@ are used in multicast ethernet and IPv6 neighbour discovery. If this option is
 not present these multicast packets are discarded as most users do not need or
 understand them.
 .TP
+\-L
+set the TTL for the hole punching packet. This is an advanced flag to make
+sure that the registration packet is dropped immediately when it goes out of
+local nat so that it will not trigger some firewall behavior on target peer.
+Actually, the registration packet is only expected to make local nat UDP hole
+and is not expected to reach the target peer, see
+https://tools.ietf.org/html/rfc5389. To achieve this, the flag should be set as
+nat level + 1. For example, if we have 2 layer nat in local, we should set -L 3.
+Usually we know exactly how much nat layers in local.
+If we are not sure how much nat layers in local, we can use traceroute on
+Linux to check. The following example shows a local single layer nat because on
+second jump it shows a public ip address. In this case it should set -L 2.
+
+$ /usr/sbin/traceroute -w1 8.8.8.8
+traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 60 byte packets
+ 1  192.168.3.1 (192.168.3.1)  0.464 ms  0.587 ms  0.719 ms
+ 2  112.65.17.217 (112.65.17.217)  5.269 ms  7.031 ms  8.666 ms
+
+But this method does not always work due to various local network device policy.
+.TP
 \-v
 more verbose logging (may be specified several times for more verbosity).
 .SH ENVIRONMENT