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

interface/lib/classes/db_mysql.inc.php

interface/lib/classes/listform.inc.php

interface/lib/classes/plugin_backuplist.inc.php

interface/lib/classes/quota_lib.inc.php

interface/lib/classes/tools_monitor.inc.php

interface/web/admin/lib/lang/de_directive_snippets_list.lng

interface/web/admin/lib/lang/en_directive_snippets_list.lng

interface/web/admin/list/directive_snippets.list.php

interface/web/admin/templates/directive_snippets_edit.htm

interface/web/admin/templates/directive_snippets_list.htm

interface/web/admin/templates/firewall_edit.htm

interface/web/admin/templates/firewall_list.htm

interface/web/admin/templates/groups_edit.htm

interface/web/admin/templates/groups_list.htm

interface/web/admin/templates/iptables_edit.htm

interface/web/admin/templates/iptables_list.htm

interface/web/admin/templates/language_add.htm

interface/web/admin/templates/language_complete.htm

interface/web/admin/templates/language_edit.htm

interface/web/admin/templates/language_export.htm