text: Title: In a Jupyter notebook, no display when poof is in a separate cell
  Body: if visualizer.poof() is called in a separate cell, no visualization appears, as the empty plot has already been rendered in the call for fit(). Workaround is to access visualizer.ax.get_figure().
  
  ### Issue
  
  For extra detail, see demo notebook linked in Background section
  
  ### Code Snippet
  
  Tested using the bike share data set from the YB intro
  
  In one cell:
  ```
  visualizer = Rank1D()
  visualizer.fit(X,y)
  visualizer.transform(X)
  ```
  
  In a separate cell:
  `visualizer.poof()`
  
  ### Background
  
  Demo notebook
  https://gist.github.com/fdion/d645e164f6969d269aff681efa31ef96
  