Merge branch 'master' of http://git.ispconfig.org/ispconfig/ispconfig3

interface/lib/classes/plugin.inc.php

interface/lib/classes/tform_actions.inc.php

interface/lib/classes/tform_base.inc.php

interface/lib/classes/tpl.inc.php

interface/lib/classes/tpl_cache.inc.php

interface/web/admin/templates/directive_snippets_edit.htm

interface/web/sites/templates/web_vhost_domain_edit.htm

server/conf/vhost.conf.master

server/lib/classes/plugins.inc.php

server/lib/classes/tpl.inc.php

server/lib/classes/tpl_cache.inc.php

server/plugins-available/apache2_plugin.inc.php

server/plugins-available/nginx_plugin.inc.php