23 - Add "requests" support

[mmulich]

Requests uses a bundled urllib3, here's what I had to do to make wsgi_intercept work with it:

I propose that we add this in a requests_intercept module (with cleaned up imports ;) )

def install_opener():
    # httplib patch
    from wsgi_intercept.httplib_intercept import install
    install()

```
# requests' patch
import wsgi_intercept
from requests.packages.urllib3 import connectionpool

connectionpool.old_http = connectionpool.HTTPConnection
connectionpool.HTTPConnection = wsgi_intercept.WSGI_HTTPConnection

connectionpool.old_https = connectionpool.HTTPSConnection
connectionpool.HTTPSConnection = wsgi_intercept.WSGI_HTTPSConnection

# we need settimeout()
wsgi_intercept.wsgi_fake_socket.settimeout = lambda self, timeout: None
```

def uninstall_opener():
    # httplib unpatch
    from wsgi_intercept.httplib_intercept import uninstall
    uninstall()

```
# requests' unpatch
import wsgi_intercept
from requests.packages.urllib3 import connectionpool

connectionpool.HTTPConnection = connectionpool.old_http
connectionpool.HTTPSConnection = connectionpool.old_https
```

Original link: http://code.google.com/p/wsgi-intercept/issues/detail?id=23