Squashed 'extensions/piwik/' content from commit 30cb10b

git-subtree-dir: extensions/piwik
git-subtree-split: 30cb10b785d87ca4d3449fc3b900adc35c0ea248
Merge commit '4fbd2089a26506d1a9e5c4528f4b17b03ca462db' as 'extensions/piwik'
Merge branch 'master' of github.com:weimarnetz/wiki