Note: State store order information of the emissions. Classic HMMS have emission order 0, that is the emission probability is conditioned only on the state emitting the symbol.For higher order emissions, the emission are conditioned on the state s as well as the previous emission_order[s] observed symbols.
The emissions are stored in the state's usual double* b. The order is set state.order.
Note: state.order != NULL iff (model_type & kHigherOrderEmissions) == 1