Cassette support for multiprocessing

[sweenzor]

Currently, if you use cassette within a multiprocess created process, it will not save the recorded responses.

Simple example wherein "responses.yaml" is not created

import multiprocessing
import urllib2

import cassette


def hi(*args):

    r = urllib2.urlopen("http://www.internic.net/domain/named.root")
    r = urllib2.urlopen("http://www.internic.net/domain/named.root")

    assert "A.ROOT-SERVERS.NET" in r.read(10000)


if __name__ == '__main__':
    cassette.insert("responses.yaml")

    p = multiprocessing.Process(target=hi)
    p.start()
    p.join()

    cassette.eject()