New pygments syntax highlighting.

Now use the "friendly" theme. It was generated using "python pygmentize -f html -S friendly -a .highlight > syntax.css"
Added files for exclusion from _site
Only show post excerpts on main site.

Instead of showing the full article on the front page, only show an excerpt together with an expansion link.
Added categories and proper syntax highlighting.
Fixed wrong path to sidebar icon.
Added proper name to RSS feed.
Added new site icons and removed the old ones.