The Celtics were busy on Friday, first with the news that they had signed Darius Miles and then Bill Walker. This gives the Celtics 15 players under contract, the maximum number allowed. So, the roster is complete. There will be some pretty good battles in training camp as several unproven players try to prove that they can do the job. The fact that Miles is able to play again after what was considered a career ending injury shows that he has a lot of motivation and is working hard to make it...