* setup_firewall sets the firewall up.
* restore_firewall restores the firewall to initial state.

When executing with the option --syslog start redirecting to
syslog immediately after the command line options are validated.
This way when using with some init daemon, e.g., upstart all the
relevant information (connection failures, etc) can be retrieved from
the log instead of being lost to stdout or stderr.

Closes: #40

This is no longer used by modern MacOSX and not getting tested.

It also required a do_wait() function which was a complication for
sshuttle as a whole.

Can get resurrected if required.

Closes: #36.

Python 3.0, 3.1, 3.2, and 3.4 not supported however.

We will log the errors, however no point in failing; not only can this
hide errors that occured setting up the firewall, but is pointless as we
can't actually handle these errors in a good way anyway.

Fix bug reported by @matiwinnetou in #31

None >= 1 not valid under Python3.

Fixes #31.

Add tests_require into setup.py

pytest and mock are needed for running tests.

This needs to be redone; will do so at a later stage.