Here is my proposed fix_urllib. The transform function is massive
because there are a lot of cases, so maybe I should break it into
separate functions for each case, and it could maybe do with some more
documentation as well. I also use FromImport from fixer_util.py even
though it warns against doing so for dotted imports because it appears
to work. The temp.py file is a dummy python file that you can test it on
to get an idea of what it does. I think it's got all the desired
functionality, but I'm not an expert on the urllib changes so let me
know if I missed anything. I haven't written tests for it yet, but
assuming it looks reasonable, I can do that later today or tomorrow.