text: Title: Jupyter>>nbviewer slides Fail, notebook view fine
  Body: When using the web based iPython Notebook/Jupyter capability, i created a notebook with markdown cells of text and code cells to display the code and plots for matplotlib and bokeh. I then download that as .ipynb open with sublime, copy and paste to git, then access it on nbviewer through my git account. When looking at it here: 
  http://nbviewer.ipython.org/github/angisgrate/test/blob/master/pyohio3.ipynb
  in notebook view, it works fine. the markdown, code, and plot steps are all there. 
  When switching to slides view, the intent of the creation needed for the presentation, this code blocks occurs first, blocking out the first 10 markdown steps and all the matplotlib steps, rendering this weird code without the plots:
  http://nbviewer.ipython.org/format/slides/github/angisgrate/test/blob/master/pyohio3.ipynb 
  
  How can i fix this asap?? I've looked through and there was a similar problem in 2014 with slides, but it yielded an actual "Error" that i'm not seeing, just this contorted view 
  