Fixes#720.
Related changes: used a NamedTuple for time.struct_time on Python 3, used
sys.version selectors for proper typing of #716, added missing *Style classes
to logging on Python 3.
Add `TimeTuple = Tuple[int, int, int, int, int, int, int, int, int]`
to stdlib/3/time.pyi and stdlib/3/datetime.pyi.
Use `TimeTuple` instead of `tuple` (where relevant) in time.pyi for
stronger type checking.
Use `TimeTuple` instead of
`Tuple[int, int, int, int, int, int, int, int, int]` in datetime.pyi
to increase readability.
* Add definitions added in Python 3.3
* Remove blanks between function stubs
* Group Unix-only functions into platform checks
* Correct get_clock_info() return type to SimpleNamespace
