index.html: Add "we've left the majority behind" slides

index.html: Add "we've left the majority behind" slides

Put these in their own section.

The justified text doesn't flow very well, but the ragged right text
in Aron [1] and Greg's [2] versions don't look all that beautiful
either ;).  Personally, I think this slide would be better without any
text ;).

[1]: http://www.slideshare.net/aronahmadia/esip-2014
[2]: http://www.slideshare.net/gvwilson/dark-matter-public-health-and-scientific-computing