Add 3D Cross Section Tool to Terrain Tools

I saw this demo at the 2014 Dev Summit & thought it might be a good fit here - because this repo already has terrain tools and a GPK with terrain data ( https://github.com/Esri/vehicle-commander/tree/master/data),

It might be useful to add a 3D Cross Section/Plot Tool to this app's available Terrain Tools. Here is an elegant implementation that creates the cross section as a png: https://gist.github.com/csmoore/9965706#file-terraincrosssection-py

Just would need to display the resultant png in a pop-up form.

NOTE: The script above does have a dependency on MatPlotLib so that would require an additional configuration step to add this to the Runtime LocalServer