Use Unicode for module name and paths in the following functions:
* PyImport_ImportModuleLevel()
* add_submodule()
* ensure_from_list()
* get_parent()
* import_module_level()
* import_submodule()
* load_next()
* mark_miss()
* 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
* Document the function
* Use RegQueryValueW() instead of RegQueryValueA()
* Use _Py_fopen() instead of fopen()
* Allocate registry key on the heap, not on the stack, and handle memory
allocation failure
* Handle Python exception in find_module()
- is_builtin(), init_builtin(), load_builtin() and other builtin related
functions use Unicode strings, instead of byte strings
- Rename _PyImport_FixupExtensionUnicode() to _PyImport_FixupExtensionObject()
- Rename _PyImport_FindExtensionUnicode() to _PyImport_FindExtensionObject()
