* fix(tunnel/tor): keep tunneldir clean
This diff ensures that we don't keep the log file growing and
we also remove the temporary files created by the library we
are currently using for running tor from golang.
Part of https://github.com/ooni/probe/issues/985
* fix(session.go): tell use we're using a tunnel
* refactor(tunnel): remove nil tunnels hack
This code was originally introduced because a tunnel could be
nil in session.go. I have verified that every invocation of
tunnel.Start is careful to ensure that we have a tunnel name
and that we don't manipulate a nil tunnel.
For this reason, I'd rather remove this tricky bit of code and
further simplify the tunnel code.
Part of https://github.com/ooni/probe/issues/985
* even better docs
* feat(tunnel): introduce persistent tunnel state dir
This diff introduces a persistent state directory for tunnels, so that
we can bootstrap them more quickly after the first time.
Part of https://github.com/ooni/probe/issues/985
* fix: make tunnel dir optional
We have many tests where it does not make sense to explicitly
provide a tunnel dir because we're not using tunnels.
This should simplify setting up a session.
* fix(tunnel): repair tests
* final changes
* more cleanups
We're trying to remove a circular dependency between the measurement
Session and the tunnel package. To this end, continue to reduce the
dependency scope by providing TorArgs and TorBinary directly.
Part of https://github.com/ooni/probe/issues/985
