EvgenyKarkan/EKAlgorithms — pull request #54 by AustinChou (2014-03-16 06:17:35+00:00)
Title: Fix a problem in EKLinkedList.m

After initialised a EKLinkedList instance, then use AddToBack instance method. I found `self.tail` is nil and `self.tail.next` is nil either. And it will cause `head.next` or `node.previous` to be nil.