Add urllib3 to the docs

Update the README to reflect the modern condition.

docs/index.rst

@@ -15,6 +15,7 @@ Examples
    http_client
    httplib2
    requests
+   urllib3
    urllib
 
 

docs/urllib3.rst

@@ -0,0 +1,32 @@
+urllib3_intercept
+==================
+
+.. automodule:: wsgi_intercept.urllib3_intercept
+
+
+Example:
+
+.. testcode:: 
+
+    import urllib3
+    from wsgi_intercept import urllib3_intercept, add_wsgi_intercept
+
+    pool = urllib3.PoolManager()
+
+
+    def app(environ, start_response):
+        start_response('200 OK', [('Content-Type', 'text/plain')])
+        return [b'Whee']
+
+
+    def make_app():
+        return app
+
+
+    host, port = 'localhost', 80
+    url = 'http://{0}:{1}/'.format(host, port)
+    urllib3_intercept.install()
+    add_wsgi_intercept(host, port, make_app)
+    resp = pool.requests('GET', url)
+    assert resp.data == b'Whee'
+    urllib3_intercept.uninstall()