Added license information to articles, in sidebar.

Added license information to articles, in sidebar.

CC license images where aquired and processed using prepareimages.sh script.

    README.md
    application/views/articles/2013_06_cpp_setup.php
    application/views/sidebars/sb_article.php
    css/style.css
    images/licenses/by-flat.png       (+)
    images/licenses/by-nc-nd-flat.png (+)
    images/licenses/by-nc-sa-flat.png (+)
    images/licenses/by-nd-flat.png    (+)
    images/licenses/by-sa-flat.png    (+)
    images/licenses/prepareimages.sh  (+)