code: function normalizeCpts(cpts) {
      var probs = []
      for (var i=0; i < cpts.length; i++) {
        probs.push(normalizeProbs(cpts[i]));
      }
      return probs;
    }
docs: Normalizes a CPT.
  @param {Array} cpts Array of arrays (matrix) representing a CPT.
  @returns {Array} Normalized CPT.