#toString() changed and new Tree methods implemented
#toString() changed and new Tree methods implemented

#toString() is more verbose and uses StringBuilder now; includes info about the root, size, internal and external path lengths, internal nodes, and number of leaves in the tree
BinaryTree.BinaryNode#toString() uses StringBuilder now instead of String
BinaryTree.BinaryNode#isLeaf() added; indicates whether this binary node is a leaf or not
Implemented the new methods added into Tree: #internalPathLength(), #externalPathLength(), #leafCount(), #internalNodes()

fishnal/pv-library-java