NetworkManager and tinc

[Rob Townley]

> So if there is no objection to having the public keys stored in plain sight on
> the filesystem, then the only thing missing in tinc 1.0.x is the control
> interface to get runtime information.

On windows, there was not a way to increase debugging on the fly
because signals could not be sent, but even if there was, there were
still configuation variables that debug does not print out.  It would
be nice to have a way that would dump configuration information
because it is not always clear what the default value for a config
variable is in every situation.  PMTU config settings and its runtime
values would be helpful, for instance.