Added Flattr buttons

Yesterday I decided to start using Flattr on a regular basis. The intention is to be mainly a supporter, but I certainly won't refuse if someone insists on sending a flattr my way ☺. As a consequence, you now see a "Flattr this" button at the bottom of every page on this website - you can use this to express your general approval of the site. If you like a particular post, you can also use the button on that post. This being a Drupal site, Flattr integration naturally is realized with the Flattr module. The documentation for the module is a bit sparse, so I wrote a few notes about its configuration on my wiki.