title: Jupyter Notebooks not displaying progress bars
body: <p>I'm trying to get a progress bar going in Jupyter notebooks. This is a new computer and what I normally do doesn't seem to work:</p>
  
  <pre><code>from tqdm import tqdm_notebook
  example_iter = [1,2,3,4,5]
  for rec in tqdm_notebook(example_iter):
      time.sleep(.1)
  </code></pre>
  
  <p>Produces the following text output and doesn't show any progress bar</p>
  
  <pre><code>HBox(children=(IntProgress(value=0, max=5), HTML(value='')))
  </code></pre>
  
  <p>Similarly, this code:</p>
  
  <pre><code>from ipywidgets import FloatProgress
  from IPython.display import display
  f = FloatProgress(min=0, max=1)
  display(f)
  for i in [1,2,3,4,5]:
      time.sleep(.1)
  </code></pre>
  
  <p>produces this text output:</p>
  
  <pre><code>FloatProgress(value=0.0, max=1.0)
  </code></pre>
  
  <p>Is there a setting I'm missing to get Jupyter to display these progress bars?</p>