A Naive Bayes classifier with a fixed number of features.
The features are assumed to have integer values even though RVFDatum will return doubles.
Kristina Toutanova (email@example.com), Sarah Spikes (firstname.lastname@example.org) - Templatization. Not sure what the weights counter
is supposed to hold; given the weights function it seems to hold Pair<Pair<L, F>, Object>
but this seems like a strange thing to expect to be passed in.