The attached patch adds the following behavior to the handling
of REDUCE codes:

- A user-defined type may have a __reduce__ method that returns
  a string rather than a tuple, in which case the object is
  saved as a global object with a name given by the string returned
  by reduce.

  This was a feature added to cPickle a long time ago.


- User-defined types can now support unpickling without
  executing a constructor.

  The second value returned from '__reduce__' can now be None,
  rather than an argument tuple.  On unpickling, if the
  second value returned from '__reduce__' during pickling was
  None, then rather than calling the first value returned from
  '__reduce__', directly, the '__basicnew__' method of the
  first value returned from '__reduce__' is called without
  arguments.

I also got rid of a few of Chris' extra ()s, which he used
to make python ifs look like C ifs.