title: running "jupyter notebook" in virtualenv returning AttributeError
body: <p>I installed jupyter using pip in a virtualenv in python3. On running:</p>
  
  <pre><code>jupyter notebook
  </code></pre>
  
  <p>I get the following Error</p>
  
  <pre><code>    File "&lt;path&gt;/ss/bin/jupyter-notebook", line 7, in &lt;module&gt;
      from notebook.notebookapp import main
    File "&lt;path&gt;/ss/lib/python3.4/site-packages/notebook/notebookapp.py", line 44, in &lt;module&gt;
      from zmq.eventloop import ioloop
    File "&lt;path&gt;/ss/lib/python3.4/site-packages/zmq/eventloop/__init__.py", line 3, in &lt;module&gt;
      from zmq.eventloop.ioloop import IOLoop
    File "&lt;path&gt;/ss/lib/python3.4/site-packages/zmq/eventloop/ioloop.py", line 78, in &lt;module&gt;
      while _IOLoop.configurable_default() is not _IOLoop:
    File "&lt;path&gt;/ss/lib/python3.4/site-packages/tornado/ioloop.py", line 350, in configurable_default
      from tornado.platform.asyncio import AsyncIOLoop
    File "&lt;path&gt;/ss/lib/python3.4/site-packages/tornado/platform/asyncio.py", line 25, in &lt;module&gt;
      from tornado.gen import convert_yielded
    File "&lt;path&gt;/ss/lib/python3.4/site-packages/tornado/gen.py", line 1295, in &lt;module&gt;
      _wrap_awaitable = asyncio.ensure_future
  AttributeError: 'module' object has no attribute 'ensure_future'
  </code></pre>
  
  <p>I upgraded every dependency module to its latest version using </p>
  
  <blockquote>
    <p>--upgrade</p>
  </blockquote>
  
  <p>But it is still giving me same error.</p>