Provides {@link de.jstacs.sequenceScores.differentiable.DifferentiableSequenceScore}s that are mixtures of other {@link de.jstacs.sequenceScores.differentiable.DifferentiableSequenceScore}s.
The abstract base of all mixtures is {@link de.jstacs.sequenceScores.statisticalModels.differentiable.mixture.AbstractMixtureDiffSM},
{@link de.jstacs.sequenceScores.statisticalModels.differentiable.mixture.MixtureDiffSM} provides a default implementation.