pybullet.getAABB and getAPIVersion

fix btMultiBody::getLinkCollider
bump up Bullet C-API version

src/BulletDynamics/Featherstone/btMultiBody.h

@@ -142,9 +142,9 @@ public:
 
 	btMultiBodyLinkCollider* getLinkCollider(int index)
 	{
-		if (index >= 0 && index < m_colliders.size())
+		if (index >= 0 && index < getNumLinks())
 		{
-			return m_colliders[index];
+			return getLink(index).m_collider;
 		}
 		return 0;
 	}
@@ -659,7 +659,6 @@ private:
     btVector3 m_baseConstraintTorque;    // external torque applied to base. World frame.
  
     btAlignedObjectArray<btMultibodyLink> m_links;    // array of m_links, excluding the base. index from 0 to num_links-1.
-	btAlignedObjectArray<btMultiBodyLinkCollider*> m_colliders;
 
     
     //