done! sorta. first draft of fantastic-front-end-2.

    Todos:
    * add to end: example data/stats showing etagify gains.
    * halve the length without totally losing the big idea (measure what you change)
    * maybe skip the HAR file/waterfall intro stuff? seems very elementary?
    * section headings should be pithy, not leftovers from a terse outline
    * so much room for links/resources. le sigh.