Update TODO.md

Author: Swader

TODO.md

@@ -21,4 +21,4 @@ Active todos, ordered by priority
 - add more usage examples
 - work on PhpDoc consistency ($param type vs type $param)
 - get more mock responses and test against them
-- write example with custom EntityIterator (different Entity set for different API) and custom Entity (i.e. authorProfile, which parses some of the data and prepares for further use)
+- ~~write example with custom EntityIterator (different Entity set for different API) and custom Entity (i.e. authorProfile, which parses some of the data and prepares for further use)~~ done via [this](http://www.sitepoint.com/powerful-custom-entities-with-the-diffbot-php-client)