Add EKEdge Class to describe a edge’s weight and whether the graph is directed or undirected. At the same time, this class will be used for Prim & Kruskal algorithm.
Add a method to judge if a graph is directed or undirected by its edges
Merge pull request #57 from stanislaw/master

Quick Sort: add tests
Merge pull request #58 from EvgenyKarkan/new

Better -[NSArray hasDuplicates]
Merge remote-tracking branch 'upstream/master' into Development
Add AVL Tree Structure
Finish AVL Tree data structure with insert and delete operation
Merge pull request #59 from AustinChou/master

Add AVL Tree data structure with insert and delete operation
Update README.md
Add demo for EKTree and forestToBinaryTree class method to convert forest to binary tree
Add Prim MST Algorithm to EKGraph
Merge pull request #60 from AustinChou/master

Add forestToBinaryTree method for EKTree and Prim Algorithm for EKGraph
Update README.md
Cleaner -[NSArray isSorted]