liborigin 2.0.0

- breadth_first_iterator : tree< T, tree_node_allocator >
- difference_type : tree< T, tree_node_allocator >::iterator_base
- iterator : tree< T, tree_node_allocator >
- iterator_category : tree< T, tree_node_allocator >::iterator_base
- pointer : tree< T, tree_node_allocator >::iterator_base
- reference : tree< T, tree_node_allocator >::iterator_base
- size_type : tree< T, tree_node_allocator >::iterator_base
- tree_node : tree< T, tree_node_allocator >
- value_type : tree< T, tree_node_allocator >::iterator_base, tree< T, tree_node_allocator >