merge upgrade of highlight.js, add base styles to pre code, dont limit language detection in index.html #809

For the Moon and Solarized themes they had .css appended to them which was causing them to not come up.

For the Moon and Solarized themes they had .css appended to them which was causing them to not come up.

according to README, I don't include reveal.min.js.
Hence I believe it makes sense to not include reveal.min.css either.
Hence, examples added in index.html can give the feeling that they don't work yet.

use 'url()'-free path when specifying parallax image, refactor so that parallax is applied to background class, remove unused attributes #595