AVL Tree

AVL tree class that inserts and removes a node using a Binary Search Tree and balance it afterwards

                            30                              
             /                               \              
            10                               50             
     /              \                 /              \      
    5               20               40              99     
 /      \               \                         /     \   
2       7               25                       70     140 
      /                                                    
     6                                                        

Inorder: 2 5 6 7 10 20 25 30 40 50 70 99 140