Updated versions.

- Removed links to binaries of individual packages since we don't maintain those separately any more.
- Removed current/outdated markers because if we cared enough to update "current" to "outdated" we'd update the package itself.
Updated atk and harfbuzz
Use the same favicon.ico as http://hexchat.github.io/
Move normalize.min.css in _includes and update it to v3.0.1.
Use more variables.
Remove unneeded end tag.
Use html5shiv, selectivizr.js and respond.js from OSSCDN.

This actually fixes page display with IE < 9.
CSS: minor tweaks.
Losslessly compress img/dependency-graph.png.

Before: 155889 bytes
After:  105188 bytes
Explicitly disable Pygments since it's not used and set encoding to UTF-8.