A simple main that loads the dataset contained in the file
named in the first command-line argument, builds a second-order
HMM, prints it out and finds and prints the most likely state
sequence for each of the output sequences.
Returns the most likely state sequence for the given
output sequence, i.e., the state sequence of highest
conditional probability given the output sequence, according to
the second-order HMM that was provided to the constructor.