How can I disable debugging the HTTParty request - like debug_output $stderr in MWS::Base ?

I see that [debug_ouput is set here](https://github.com/elyngved/ruby-mws/blob/master/lib/ruby-mws/api/base.rb#L10)

How can I disable that? I don't want to see the headers / response from the http requests in the rails console ( on my development machine )

Thanks!
