The new version of requests un-vendors urllib3, with a nifty hack:
https://github.com/kennethreitz/requests/blob/master/requests/packages.py
Unfortunately messing directly with sys.modules causes some weird
behavior that I don't entirely understand. Avoiding the extra import to
requests.packages as part of VCR's initialization seems to sidestep the
issue.
Closes#311
This refactoring includes some PEP-8 compliance changes, as well as some more
complete testing to ensure that we're in fact serving everything out of
cassettes when we thing we are.
Incidentally, it also includes fixes for #3 and #4