[Python-3000] PATCH: library reference docs for PEP 3101

[Talin]

I just posted on the tracker a patch which adds extensive documentation 
for PEP 3101 to the Python Library Reference. This includes:

   str.format()
   format()
   __format__
   Formatter
   format string syntax
   format specification mini-language

http://bugs.python.org/issue1068

(Eric, my description of the Formatter overloaded methods may not match 
your latest revisions. Feel free to point out any errors.)

Oh, and thanks to Georg for making it possible for me to actually write 
library documentation :)

-- Talin