Adding a method that will give me information about the internal structure of the Huffman Tree.

There are two ways to test the Huffman Tree's encoding:
1. Encode something and look at the results
2. Look at the structure of the tree at a given time

The method that has been added to the tree will give us some information
about the tree's structure.
Added a Test for the Huffman Tree's encoding
Fixed small but in character insertion