Add support for redirect with cookie authentication

In relation to feedreader/pluto#39, the request cookie gets saved for each redirect. This should support cookie based authentication.

fetcher/lib/fetcher/worker.rb

@@ -154,6 +154,7 @@ def get_response( src )
 
       redirect_limit = 6
       response = nil
+      cookie = nil
       cookie_jar = nil
 
       until false
@@ -165,6 +166,7 @@ def get_response( src )
         logger.debug "GET #{uri.request_uri} uri=#{uri}, redirect_limit=#{redirect_limit}"
 
         headers = { 'User-Agent' => "fetcher gem v#{VERSION}" }
+        headers['Cookie'] = cookie unless cookie.nil?
         headers['Cookie'] = cookie_jar unless cookie_jar.nil?
 
         if use_cache?
@@ -216,6 +218,7 @@ def get_response( src )
             newuri = uri + response.header['location']
           end
           uri = newuri
+          cookie = response['Set-Cookie']
 
           cookie = response.get_fields('set-cookie')
           if cookie.respond_to?('each')