made page validate

woohoo! reveal.js is now HTML5 compliant! 

this is validated using the http://validator.w3.org/ and the http://html5.validator.nu/ services.

this was accomplished using a tad of JavaScript to get around a fullscreen bug.

This also (slightly unintentionally but helpfully) solves a tiny bug with fullscreening in old Opera 11.52 (I think, could be 11.51 or other)

added appropriate selection color

typo fix in index.html

Typo fix: let's -> lets

Cosmetic change in css/main.css

clarification of vertical/horizontal slide relation

rm extrenous whitespace

Clarified a bit how horizontal and vertical slides relate.

reveal.js was lacking a nice, simple, minimal theme. now it has one.
bam.

the old one was pink. while I don't have anything against pink, I just thought it might be good to make the highlight color dark brown instead.

themes are now available as separate css files under css/theme/, old theme option in config is no longer supported (closes #104)

now: eot, svg, ttf, woff

this way, more browsers are supported, like older Opera/Chrome/FF

improved accessibility 

added small fallback for non-font-face browsers

I gave all the <img>s alt attributes, which makes reveal.js a lot more accessible

this way things are in Impact; Impact fits much more with the visual style than does the default Arial or Calibri.

use mq to reduce font size for low resultions, max limit on width for slides set to 900px (closes #49)