Add Croatian (hr) translation

Add complete Croatian translation for Adminer, including all strings
in adminer/lang/hr.inc.php, plural forms support in lang.inc.php,
and Croatian descriptions and translations for all plugins.

plugins/foreign-system.php

@@ -191,5 +191,6 @@ class AdminerForeignSystem extends Adminer\Plugin {
 		'pl' => array('' => 'Połącz tabele systemowe (w bazach danych "mysql" i "information_schema") za pomocą kluczy obcych'),
 		'ro' => array('' => 'Conectați tabelele de sistem (în bazele de date "mysql" și "information_schema") prin chei străine'),
 		'ja' => array('' => 'システムテーブル ("mysql" と "information_schema") を外部キーを用いて接続'),
+		'hr' => array('' => 'Povezuje sistemske tablice (u bazama "mysql" i "information_schema") stranim ključevima'),
 	);
 }