Allan Heinberg has written a bonus story for July's Uncanny X-Men #526.Best known for his work on Young Avengers and television shows including Sex And The City, Grey's Anatomy and The O.C., Heinberg will be providing the back-up feature with Siege artist Olivier Coipel.When editor Nick Lowe asked if I would be interested in coming up with this story, I actually had some time to devote exclusively to