use iconv
toolbox: Add exit callback to public interface
toolbox: Improve doc comments of refcounter
toolbox: Fix hashmap
toolbox: Improve doc comments of atom and update for 032fa9bfc99e28b625d5ad648c8206519ac4c6a2
toolbox: Update test suite for 032fa9bfc99e28b625d5ad648c8206519ac4c6a2