Merge pull request kodecocodes#4 from hollance/master

updates

Author: mitghi

AVL Tree/AVLTree.playground/Contents.swift

@@ -0,0 +1,30 @@
+//: Playground - noun: a place where people can play
+
+let tree = AVLTree<Int, String>()
+
+tree.insert(5, "five")
+print(tree)
+
+tree.insert(4, "four")
+print(tree)
+
+tree.insert(3, "three")
+print(tree)
+
+tree.insert(2, "two")
+print(tree)
+
+tree.insert(1, "one")
+print(tree)
+print(tree.debugDescription)
+
+let node = tree.search(2)   // "two"
+
+let minim = tree.root?.minimum()!  // node 1
+var succ = minim!.successor()!     // node 2
+succ = succ.successor()!           // node 3
+succ = succ.successor()!           // node 4
+succ = succ.successor()!           // node 5
+succ.successor()                   // nil
+
+tree.delete(2)