* added function for setting buffer size in CheckedInputStream
* added function to retrieve number of symbols in Huffman tree
* modified Huffman tree creation to be more flexible on inputs
* fixed memory leak in PosixThread concerning stack size setting
* added typedefs to GetObject
* added external memory variants of functions in Utf8String
* moved creation of Huffman shaped wavelet trees from utf8 encoded
  data to its own file