fixed some outstanding issues with Bullet soft bodies:

1) re-allocate a pool allocator, if one of the soft body collision algorithms is larger than max pool element size
2) manage child shapes properly, and call RemoveReferences on the m_sparsesdf

src/BulletCollision/CollisionDispatch/btDefaultCollisionConfiguration.h

@@ -48,6 +48,8 @@ struct	btDefaultCollisionConstructionInfo
 class	btDefaultCollisionConfiguration : public btCollisionConfiguration
 {
 
+protected:
+
 	int	m_persistentManifoldPoolSize;
 	
 	btStackAlloc*	m_stackAlloc;
@@ -56,6 +58,7 @@ class	btDefaultCollisionConfiguration : public btCollisionConfiguration
 	btPoolAllocator*	m_persistentManifoldPool;
 	bool	m_ownsPersistentManifoldPool;
 
+
 	btPoolAllocator*	m_collisionAlgorithmPool;
 	bool	m_ownsCollisionAlgorithmPool;