hightlight.js (+style.css) update to add clojurescript highlighting

I've been having fun making d3 clojurescript blocks, but the syntax hightlightling is currently all wonky:

http://bl.ocks.org/4409139#quadtree.cljs

So I downloaded a fresh copy of highlight.js 7.3 with clojurescript (and coffeescript) support, and used this to replace the existing hightlight.min.js. I then in a separate commit added a few lines in style.css to have clojurescript hightlight analogously to the existing javascript styles. The overall result can be currently be seen here:

http://cryptic-wildwood-1262.herokuapp.com/4409139#quadtree.cljs

(one other change I slipped in was to color javascript literals [true/false] with the same styles as numbers. That's also in its own commit ee48a5ac818dca62f971bcc2e580fd2fee62a97b and can be reverted if not wanted)

Mike - your call if you want to support blocks in other languages, but I'm hoping so! :bowtie: