code: public final void conjugate(Quaternion q1) {
  		this.x = -q1.x;
  		this.y = -q1.y;
  		this.z = -q1.z;
  		this.w = q1.w;
  	}
docs: Sets the value of this quaternion to the conjugate of quaternion q1.
  @param q1 the source vector