allow silencing upload/download

[grosser]

would be great if I could pass verbose: false or so to these to make things a little less noisy ... atm I'm using a global silence which is not threadsafe ...

  def silence_sshkit
    old = SSHKit.config.output_verbosity
    SSHKit.config.output_verbosity = :WARN
    yield
  ensure
    SSHKit.config.output_verbosity = old
  end

[will-in-wi]

That would make sense to me. Would you be willing to attempt a patch?

[grosser]

I'll take a look