[stdlib-sig] Changing the 2.6 renames to not break pickle

[Brett Cannon]

Apparently pickle doesn't like the way renames have been handled in
2.6 and people don't want to mess with pickle, so that means the
renames need to change.

So, here is my idea (only need to care about modules that have stuff
to pickle, e.g., don't need to change test.support):

* Rename lib-old to lib-new

* Change the names in lib-new to the new names.

* Change the names in the stdlib to the old names.

* Move the Py3K warnings out of the stubs in lib-new and put them in
the modules directly stored in the stdlib.

* Change the imports in the stubs in lib-new to import the old name
and suppress the Py3K warning (probably use
test.support.catch_warning() with a *very* specific ignore filter).

I think that gets __module__ set to the old module name even when code
is imported with the new name. It should also allow the Py3K warnings
to stick around without causing issues when importing from the new
name or suppressing other Py3K warnings. What do people think?

-Brett