Brieman cat branch

Should you be checking testInCount and testOutCounts instead of inCounts and outCounts? Is there a reason we do this here but not at the same spot in createNClassCategoricalNode? Could we factor out a function like double calculateScore(testValCounts, inCounts, outCounts) that would return 0 (OR MIN_SCORE) in the case of all these calls to 'continue' or return the score if necessary so this code isn't duplicated