Bullet : simple 6DOF lock (Z axis lock)

Continuing the discussion from Lock Z axis:
Some people tried to lock an axis to make theirs game “2D” but they had to do a workaround (see above), because these methods wasn’t available in the bullet native wrapping :

rigidBody.setLinearFactor( new Vector3f(1,1,0));
rigidBody.setAngularFactor( new Vector3f(0,0,1)); 

So i added those methods into the bullet warping also thanks to @normen who explained how to make such change.

The problem is that these methods aren’t available for jBullet.

Edit : those changes are merged into 3.1