Added rss feed of twitter favorites.
Including query string (e.g. user=foo) in canonical atom link to allow multiple feeds in the same reader.
Merge pull request #3 from georgedorn/master

merge from @georgedorn : added new favoritesrss.php (user favorites RSS feed) + query string in canonical atom link for userrss.php + favoritesrss.php to allow multiple user / favorites timelines in same reader