Fixed framework search paths for CHDataStructures-iOS project. Fixed CHBinaryTreeNode, CHSinglyLinkedListNode, and CHDoublyLinkedListNode object to be __unsafe_unretained for use with ARC. Removed hidden visibility for kCHPointerSize as the symbol was being duplicated in dependent projects.
Added CocoaPods CHDataStructures podspec.
Merge pull request #1 from mpurland/master

Fixes ARC and project compatibility