matricesDiffer = function(one, two) {
  if (one === two) {
    return false;
  }
  return !one || !two ||
    one[12] !== two[12] ||
    one[13] !== two[13] ||
    one[14] !== two[14] ||
    one[5] !== two[5] ||
    one[10] !== two[10] ||
    one[1] !== two[1] ||
    one[2] !== two[2] ||
    one[3] !== two[3] ||
    one[4] !== two[4] ||
    one[6] !== two[6] ||
    one[7] !== two[7] ||
    one[8] !== two[8] ||
    one[9] !== two[9] ||
    one[11] !== two[11] ||
    one[15] !== two[15];
}
Unrolls an array comparison specially for matrices. Prioritizes
checking of indices that are most likely to change so that the comparison
bails as early as possible.

@param {MatrixMath.Matrix} one First matrix.
@param {MatrixMath.Matrix} two Second matrix.
@return {boolean} Whether or not the two matrices differ.