REPL doc system

We should integrate with the Julia doc system. I had two ideas for this:
1. Hook into `@doc` do provide plain text help at the REPL. The way I see that going is that we populate the help on the fly using the plotly-schema.json file that is the source of this page: https://plot.ly/javascript/reference/. What I had in mind was `?scatter` would print the main text describing the scatter trace and then list out all the attributes. The user could then do `?scatter.attribute_name` to get the specific help entry for that attribute
2. Provide a more interactive html-based help that is served in an electron window. This would use the same data, but present a more easily readable and navigatible version of the page I linked to above. I envision it as a mathematica style documentation system. As a start to making the linked to page more readable we could just throw every item into some collapsable HTML element so users just see a list of the 12ish traces at first and can click their way through to more detail as needed. Then they don’t get the monster wall of text that the attribute reference page is right now