Merge branch 'stable-3.1'

install/sql/incremental/upd_dev_collection.sql

install/sql/ispconfig3.sql

interface/web/client/form/client.tform.php

interface/web/client/form/client_template.tform.php

interface/web/client/form/reseller.tform.php

interface/web/client/lib/lang/de_client.lng

interface/web/client/lib/lang/de_client_template.lng

interface/web/client/lib/lang/de_reseller.lng

interface/web/client/lib/lang/en_client.lng

interface/web/client/lib/lang/en_client_template.lng

interface/web/client/lib/lang/en_reseller.lng

interface/web/client/templates/client_edit_limits.htm

...face/web/client/templates/client_template_edit_limits.htm

interface/web/client/templates/reseller_edit_limits.htm

interface/web/sites/form/web_vhost_domain.tform.php

interface/web/sites/lib/lang/de_web_vhost_domain.lng

interface/web/sites/lib/lang/en_web_vhost_domain.lng

interface/web/sites/templates/web_vhost_domain_edit.htm

interface/web/sites/web_vhost_domain_edit.php