stylesheet.css:
* remove unneeded !important
* fix inefficient rule
* don't hide aside in low resolutions
* use classes more
* update normalize.css
update version
Losslessly compress png files with https://github.com/subzey/zopfli-png.
stylesheet.css:
* Fix section h1:before with small resolutions
* Remove code and pre from normalize.css since stylesheet.css already has them
Update js/pack.js with the latest uglify-js.