removed wp-piwik from mu-plugins

wp-content/mu-plugins/wp-piwik/css/wp-piwik.css

wp-content/mu-plugins/wp-piwik/dashboard/.htaccess

wp-content/mu-plugins/wp-piwik/dashboard/browsers.php

wp-content/mu-plugins/wp-piwik/dashboard/footer.php

wp-content/mu-plugins/wp-piwik/dashboard/header.php

wp-content/mu-plugins/wp-piwik/dashboard/keywords.php

wp-content/mu-plugins/wp-piwik/dashboard/overview.php

wp-content/mu-plugins/wp-piwik/dashboard/pages.php

wp-content/mu-plugins/wp-piwik/dashboard/plugins.php

wp-content/mu-plugins/wp-piwik/dashboard/screens.php

wp-content/mu-plugins/wp-piwik/dashboard/systems.php

wp-content/mu-plugins/wp-piwik/dashboard/visitors.php

wp-content/mu-plugins/wp-piwik/dashboard/websites.php

wp-content/mu-plugins/wp-piwik/gpl-3.0.html

...ontent/mu-plugins/wp-piwik/js/jqplot/IMPORTANT_NOTICE.txt

wp-content/mu-plugins/wp-piwik/js/jqplot/MIT-LICENSE.txt

wp-content/mu-plugins/wp-piwik/js/jqplot/README.txt

wp-content/mu-plugins/wp-piwik/js/jqplot/copyright.txt

wp-content/mu-plugins/wp-piwik/js/jqplot/excanvas.min.js

wp-content/mu-plugins/wp-piwik/js/jqplot/gpl-2.0.txt