2023-12-31: Replaces ecd with gnorm. Removes Oxford-Man related functions.
2019-12-05: Bug fix release. Uses is(a,b) instead of class(a)==b.
2018-02-28: Bug fix release. The format for Oxford-Man volatility file has changed.
2017-04-13: The first public release. MLE optimizer is implemented according to Zucchini's book on HMM.