integer-simple by default

[Yitzchak Gale]

I wrote:
>> As another data point, Python has also re-invented the GMP
>> wheel, likely for the same licensing reasons. They have
>> been using a simple implementation of Karatsuba
>> multiplication for years. I have never heard of anyone
>> complaining about it

Greg Fitzgerald wrote:
> Looks like they swapped out their integer implementation for Python3

Interesting! This will be new in Python 3.2 - the first changes in many
years. It's not exactly swapped out, but there are many changes.
At first glance, it looks like better 64-bit support, a new division
algorithm via floating-point, a new exponentiation algorithm
using a 5-bits-at-a-time trick in some cases, optimized Read
and Show instances (pardon the expression), a few other things.
A lot of the new stuff seems to be from HAC. As before, everything
is fully explained in expository comments inside the code, with
references; a worthwhile read. Multiplication is still the same basic
idea though - naive up to about 2000 bits, followed by just
Karatsuba and nothing more.

Thanks,
Yitz