[PATCH] Base.save should retain prefix_options

This is similar to https://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets... - in the sense that when you find an ActiveResource object (which is nested inside another AR), and then call save on it, the prefix_options are lost. This means that any subsequent calls to save or reload would not work without finding the object again.

The fix would be (in ActiveResource::Base) :

      def load_attributes_from_response(response)
        if response['Content-Length'] != "0" && response.body.strip.size > 0
          load(@prefix_options.stringify_keys.merge(self.class.format.decode(response.body)))
        end
      end