After some time offline, this website is here again. Annoyingly, it was hacked to mine Bitcoins - by people who I assume are only half nice. So I had to take the site offline to do some troubleshooting and reinstall the server completely... 😕 ...but better safe than sorry.
Now the bugs are fixed and the website is finally back online - only with encrypted connection. And even a bit faster than before. 🙂