Corrected error in generateHMM.py

Was finding MLE prob of instances wrong by p_wrong(w | t) = C(t, w) /
C(w), now corrected to p_right(w|t) = C(t, w) / C(t).

Added some info to print at program end, noted in code that prob are not
normalized; I don't think it has to be for viterbi.