Add spritz style reading mode

[popey]

http://www.spritzinc.com/ looks neat. Perhaps Beru could lead the way and be an early adopter of similar technology. I see someone has made a similar open version https://github.com/Miserlou/OpenSpritz

[rschroll]

Honestly, that looks exhausting to me. I don't see me implementing
this, but I'll leave the issue open in case someone else is interested.

If I understand their claims correctly, the magic behind Spritz is that
they align the words so that the point you focus on to recognize the
work is at the same place in all of them. Words that require one or
more saccades are split. OpenSpritz doesn't do any of this; it just
has a complicated way of doing text-align: center.