- merged different fixes and updates from foreign branches

install/install.php

install/lib/installer_base.lib.php

install/sql/ispconfig3.sql

install/tpl/server.ini.master

interface/lib/classes/functions.inc.php

interface/lib/classes/listform.inc.php

interface/lib/classes/remote.d/client.inc.php

interface/lib/classes/tform_base.inc.php

interface/lib/classes/validate_password.inc.php

interface/web/admin/directive_snippets_edit.php

interface/web/admin/directive_snippets_list.php

interface/web/admin/form/directive_snippets.tform.php

interface/web/admin/form/server_config.tform.php

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/server_config_server_edit.htm

interface/web/client/client_del.php

interface/web/client/client_list.php

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