Add a --follow-redirect option to ronin http

[postmodern]

Add a --follow-redirect option to ronin http that causes it to follow the Location URL (use uri.merge(locatation) to normalize any relative paths) redirect responses. It should perform the first request, then check the response, if it's a Net::HTTPRedirect response then perform subsequent GET requests for each Location URL, printing each redirect response as it's received, until a non-Net::HTTPRedirect is returned.