imports e.g. test_support must do so using an absolute package name
such as "import test.test_support" or "from test import test_support".

This also updates the README in Lib/test, and gets rid of the
duplicate data dirctory in Lib/test/data (replaced by
Lib/email/test/data).

Now Tim and Jack can have at it. :)

right way").  Fiddle __future__.py to use them.

Jeremy's pyassem.py may also want to use them (by-hand duplication of
magic numbers is brittle), but leaving that to his judgment.

Beef up __future__'s test to verify the exported feature names appear
correct.

    #449043 supporting __future__ in simulated shells
in support of PEP 264.

Much has changed from the patch version:
+ Repaired bad hex constant for nested_scopes.
+ Defined symbolic CO_xxx names so global search will find these uses.
+ Made the exported list of feature names explicit, instead of abusing
  __all__ for this purpose (and redefined __all__ accordingly).
+ Added gross .compiler_flag verification to test___future__.py, and
  reworked it a little to make use of the newly exported explicit list
  of feature names.

Suggested on c.l.py by William Tanksley, and I like it.

therein are of the proper form.