- Fix bug in fill_bitset() causing the bits to be set in reverse order.
- HCTree class is now encoding and decoding values using the huffman
  tree. Additionally, it uses a map and Code struct to quickly encode
  values by keeping a map of symbols and their associated codes.
- Added very simple tests that will need to be expanded upon when
  BitOutputStream is complete.
- HCTree class currently has lots of cout's for testing purposes.