* add favicon.ico
* add html5shiv, selectivizr and respond.js
* use normalize.css instead of reset
* specify <meta http-equiv="X-UA-Compatible" content="IE=edge">
* remove units from 0 in stylesheet.css
* remove the unused main.js
Losslessly compress images.
Remove bg_hr.png.

Use border-bottom instead.
index.md: Add image dimensions.
index.md: reindent for better readability.
stylesheet.css: clean up font properties.