Deprecate tabs for indenting (was Re: Indenting with tabs vs spaces)

[Tim Peters]

[William Park]
> One solution that has been proposed long ago (and many time since) is
> end-block keywords like shell.

Let's see.

for i in range(10):
    if i % 2 == 0:
        print i, i**2
    shell
shell

Yup, that works.  I'll add

    from __future__ import shell

to 2.2 if it will stop this discussion <wink>.