0.4.1 missing response body for XSS module

Created by: bsedat

Noticing that for a number of modules (like XSS) the response body is not getting stored.

After doing some digging, I think auditor.rb may need to be updated. Typhoeus::Response#headers returns a string, so I think the call to it may need to get changed to #headers_hash. In addition, using the Typhoeus::Response#content_type you define would be nifty, although Arachni::Page would possibly need something similar in that case.