made the site structure jekyll compliant

- added jekyll default folders
- added a couple of articles in _posts folder
first usable version after switching to jekyll

- changed markdown parser to redcarpet
- added a redcarpet plugin that handles line numbers
- updated Gemfile
- added two articles on Go and fixed formatting (liquid is a quite
annoying templating system)
- created default and post layout
- took advantage of include files for header and footer
- added a bunch of assets
- switched the pygments code theme to solarized dark
- created about page