function identity(out) {
    out[0] = 0;
    out[1] = 0;
    out[2] = 0;
    out[3] = 1;
    out[4] = 0;
    out[5] = 0;
    out[6] = 0;
    out[7] = 0;
    return out;
  }
Set a dual quat to the identity dual quaternion

@param {quat2} out the receiving quaternion
@returns {quat2} out