update to asyncore in Python library

[jeremy@z...]

I just made a few small changes to the asyncore module in the Python
source tree, which I thought I'd mention here. It's hard to tell if
this is the only drift between the two copies of asyncore, because
we've "normalized whitespace" in our copy and diff isn't too helpful
anymore. 

The key change is to remove the definintions of EWOULDBLOCK and
company for os.name == "nt". On Windows, the errno module gets these
definitions from winsock.h. So errno should be correct across
platforms. Is there any Windows variant where this wouldn't be true?

I also wrapped some long lines.

Jeremy