In :mod:`tkinter`, the *name* parameter of the
:meth:`~tkinter.Misc.wait_variable`, :meth:`~tkinter.Misc.setvar` and
:meth:`~tkinter.Misc.getvar` methods and the *value* parameter of
:meth:`!setvar` are now required.  Their former default values
(``'PY_VAR'`` and ``'1'``) were not meaningful.
