text: Title: Bug: Output gets hidden on stop_and_persist in Jupyter notebooks
  Body: <!-- Please use the appropriate issue title format:
      BUG REPORT
      Bug: {Short description of bug}
  
      SUGGESTION
      Suggestion: {Short description of suggestion}
  
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  ## Description
  Currently, in jupyter notebooks, the final `stop_and_persist` output is not persisted. I've opened an issue in ipywidget for understanding the issue a little better (https://github.com/jupyter-widgets/ipywidgets/issues/2072).
  
  ### System settings
  
  - Operating System: Mac OS 10.13.1
  - Terminal in use: NA
  - Jupyter version: 4.4.0
  - Python version: 2.7.14
  - Halo version: 9f9ea376d43f0d43859f7ddeee68e34834fdbf19
  - `pip freeze` output: NA
  
  
  ### Error
  The output display is not persited on `stop_and_persist` call.
   
  ### Expected behaviour
  The output should be persited on `stop_and_persist` call.
  
  ## Steps to recreate
  
  ![widget bug](https://user-images.githubusercontent.com/5673050/40014254-ae56e4e8-57cd-11e8-888b-3ab466977862.gif)
  
  ## People to notify
  @JungWinter @ManrajGrover