Fix show replay messages when using wireless network

Traceback (most recent call last):
  File "/opt/re6stnet/re6stnet", line 403, in main
    tunnel_manager.handlePeerEvent()
  File "/cygdrive/d/slapos/opt/git/re6stnet/re6st/tunnel.py", line 472, in handlePeerEvent
    self.sock.sendto('\1' + ''.join(msg), address)

This fixes a regression introduced with new protocol to registry (commit
e24eb3f5), which can't transport None value.

Conflicts:
	re6stnet

This is a common misconfiguration that may break internet acces for other peers.

We also stop checking for child process termination when used without tunnel
manager (i.e. with --client or --client-count=0) because it conflicts with the
'ip route' command that is called every minute if --table=0 is used.
Anyway, with a tunnel manager, only openvpn client are watched.

- authenticated communications with registered clients
- XML-RPC is dropped
- multi-threaded server

Keep option --persist-tun of openvpn in the Cygwin.
Add tap-drivers before babeld opened.

Add subnet route at artup;
Remove --persist-tun for openvpn;

When get ipv6 route table, netsh return interface index other than
name in the Windows 7.

Add function TunnelManager._get_win32_ipv6_route_table.

When a peer advertised several addresses, a node trying to create a tunnel to
it never tried any other address than the first one.

Before, we wrongly assumed OpenVPN would try all addresses before aborting
(--ping-exit). New code reexecutes OpenVPN until all addresses are tried
and update the peer db to reorder addresses if the first one failed.