improve serialization based on feedback: make it easier to serialize a single object, or single shape, or single bvh.
Modified Bullet/Demos/ConcaveDemo to use btSerializer to serialize the btOptimizedBvh (or optionally the trimesh+bvh)
You can also serialize trimesh without BVH, use:
serializer->setSerializationFlags(BT_SERIALIZE_NO_BVH);// or BT_SERIALIZE_NO_TRIANGLEINFOMAP