normalize method

double normalize ()

Normalize this.

Implementation 

double normalize() {
  final double l = length;
  if (l == 0.0) {
    return 0.0;
  }
  final double d = 1.0 / l;
  _qStorage[0] *= d;
  _qStorage[1] *= d;
  _qStorage[2] *= d;
  _qStorage[3] *= d;
  return l;
}