create branch v2.2.
refactoring nonmutating algorithm.
refactoring nonmutating algorithm.
refactoring algo_find_if().
refactoring algo_adjacent_find and algo_adjacent_find_if.
refactoring algo_find_first_of and algo_find_first_of_if.
refactoring algo_count and algo_mismatch.
refactoring algo_mismatch and algo_equal.
refactoring algo_equal_if and algo_search.
refactoring algo_search, algo_search_if and algo_search_n.
refactoring algo_search_n and algo_search_n_if.
modify gitignore.
refactoring algo_search_end and algo_find_end.
refactoring algo_search_end_if and algo_find_end_if.
refactoring algo_search_end_if, algo_find_end_if, algo_copy, algo_copy_n and algo_copy_backward.
refactoring algo_copy_backward.
refactoring algo_swap, algo_iter_swap, algo_swap_ranges and algo_transform.
refactoring algo_transform.
refactoring algo_transform_binary.
refactoring algo_replace.