Merge pull request #59 from AustinChou/master

Add AVL Tree data structure with insert and delete operation
Update README.md
Merge pull request #60 from AustinChou/master

Add forestToBinaryTree method for EKTree and Prim Algorithm for EKGraph
Update README.md
Cleaner -[NSArray isSorted]
Merge pull request #61 from EvgenyKarkan/new

Cleaner -[NSArray isSorted]
Format.
Merge branch 'master' of https://github.com/EvgenyKarkan/EKAlgorithms
Merge remote-tracking branch 'upstream/master'