Merge pull request #53 from stanislaw/master

Better -[NSArray indexesOfMinimumAndMaximumElements]
#HolyCow - this is Xcode update commit. :)
Fix the problem that self.tail is nil when call AddToBack method after a linked list is initialized.
Add some basic data structure.
Keep addToFront act as addToBack
Merge pull request #54 from AustinChou/master

Fix a problem in EKLinkedList.m
Removed Foundation imports. Thank you pre-compiler header ;)
Update README.md
Finish find method in EKBSTree
Finish deleteObject method and add a parent property to EKBTreeNode
Add some unit tests
Merge pull request #55 from AustinChou/master

Finish find & delete method in EKBSTree Class
Add Cartesian quadrants selection algorithms.
Update README
Cartesian quadrants selection: a bit faster bitwise algorithm
Merge pull request #56 from EvgenyKarkan/new

Add Cartesian quadrants selection algorithms.
Update README.md
Cartesian quadrant selection: add one more bitwise algorithm