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/

@mhoeber  Now I am not sure what you meant by including Windows 7 in the header of the other tables. Was it meant to indicate minimum OS version? If so, what is meant by the Mac OSX 10.8 or 10.9 header? Confusing. 
What I was trying to indicate by making this change to the table for Insights is that Dennis tested everything shown for the other two products, and that he also tested IE 11 on Windows 8 only.