Implementation of TOC for articles (blog, news, documentation). Based on
- https://github.com/ghiculescu/jekyll-table-of-contents
- http://stackoverflow.com/questions/7985081/how-to-deploy-a-jekyll-site-locally-with-css-js-and-background-images-included

Several options available to customize toc() behaviour. In addition we
may add a CSS...
Merge pull request #88 from jouvin/jekyll-toc

Implementation of TOC for articles (blog, news, documentation).