public static class FrameUtils.CategoricalBinaryEncoder
Helper to convert a categorical variable into a "binary" encoding format. In this format each categorical value is
first assigned an integer value, then that integer is written in binary, and each bit column is converted into a
separate column. This is intended as an improvement to an existing one-hot transformation.
For each categorical variable we assume that the number of categories is 1 + domain cardinality, the extra
category is reserved for NAs.