Updated Czech language files and improved language file import script.

interface/lib/lang/cz.lng

interface/web/admin/language_import.php

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

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

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

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

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

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

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

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

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

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

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

interface/web/dashboard/lib/lang/cz_dashlet_products.lng

interface/web/dashboard/lib/lang/cz_dashlet_shop.lng

interface/web/dns/lib/lang/cz_dns_slave.lng

interface/web/dns/lib/lang/cz_dns_soa.lng

interface/web/mail/lib/lang/cz_xmpp_domain.lng

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

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