[Python-3000] PEP 3101 Updated

[Eric Smith]

Talin wrote:
> Alex Holkner wrote:
>> What is the behaviour of whitespace in a format specifier?  e.g.
>> how much of the following is valid?
>>
>>       "{  foo . name  : 20s }".format(foo=open('bar'))
> 
> Eric, it's your call :)

I'm okay with whitespace before the colon (or !, as the case may be). 
After the colon, I'd say it's significant and can't be automatically 
removed, because a particular formatter might care (for example, "%Y %M 
%D" for dates).

Currently the code doesn't allow whitespace before the colon.  I can add 
this if time permits, once everything else is implemented.