public Quaternion mult(Quaternion q) {
        return mult(q, null);
    }
Multiplies by the argument and returns the product as a new instance.
The current instance is unaffected.

<p>This method is used to combine rotations. Note that quaternion
multiplication is noncommutative, so generally q * p != p * q.

@param q the right factor (not null, unaffected)
@return {@code this * q} (a new Quaternion)
jme3-core/src/main/java/com/jme3/math/Quaternion.java