:on_success take 2 parameters when called from fetch_and_parse. Closes …

…#7

README.rdoc

@@ -96,7 +96,7 @@ If you're still having issues, please let me know on the mailing list. Also, {To
 
     # defining custom behavior on failure or success. note that a return status of 304 (not updated) will call the on_success handler
     feed = Feedzirra::Feed.fetch_and_parse("http://feeds.feedburner.com/PaulDixExplainsNothing",
-        :on_success => lambda {|feed| puts feed.title },
+        :on_success => lambda {|url, feed| puts feed.title },
         :on_failure => lambda {|url, response_code, response_header, response_body| puts response_body })
     # if a collection was passed into fetch_and_parse, the handlers will be called for each one