[package] add peervpn package Makefile

[package] add peervpn package Makefile

PeerVPN (http://www.peervpn.net/), by Tobias Volk, is software that
builds virtual ethernet networks between multiple computers. A virtual
network built by PeerVPN uses a full mesh topology. All nodes talk
directly to each other, there is no need for a central server. If one
node goes down, the rest of the network is unaffected.

Configuring PeerVPN is easy. You just need to configure an encryption
key, network name and the contact information (IP address and port) of
some other PeerVPN nodes. Adding a new node to an existing network
doesn't require the existing nodes to alter their configuration,
because its IP address is automatically distributed across the whole
virtual network.

Signed-off-by: Dan VerWeire <dverweire@gmail.com>
git-svn-id: svn://svn.openwrt.org/openwrt/packages@33060 3c298f89-4303-0410-b956-a3cf2f4a3e73