R1:228c3781a2f1

Add gRaphael charting library

Summary:
I typed up like 30 pages here and then got my soul crushed by T895, but here's
the summary:

I looked at several charting libraries. There aren't very many that seem to be
any good and have an open-source license.

I also want the charts to be scriptable in JS so we can add good interactivity
where appropriate.

Raphael is an SVG drawing library which seems very solid. gRaphael is a charting
library on top of Raphael that is a lot less solid, but seems kind of OK.