Issue #3080: Use Unicode to import source and compiled modules * Use Unicode for module name and path in the following functions: * get_file() * load_source_module(), parse_source_module() * make_compiled_pathname(), check_compiled_module(), read_compiled_module(), load_compiled_module(), write_compiled_module(), update_compiled_module() * On Windows, use CreateDirectoryW() instead of mkdir() * update_compiled_module() cannot fail anymore