Ahodges/doc/doc 792

Initial, proof of concept draft, focusing initially on enrollment chapters. @shnayder , @clintonb , @dsjen , @mulby , @brianhw , @rocha , @JAAkana , @WatsonEmily , @stroilova please feel free to comment anytime on this PR from now through release.

An HTML draft is now available! http://draft-edx-insights.readthedocs.org/en/latest/

changed to "Understanding the context of the course run: the environmental factors and choices that make each run unique." 

Does that make the intention clearer, that without some contextual knowledge, you will not be able to draw conclusions from the dashboard, or use the information effectively?