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/table-indexes-structure.php

@@ -33,5 +33,6 @@ class AdminerTableIndexesStructure extends Adminer\Plugin {
 		'pl' => array('' => 'Rozszerzona tabela wyników struktury indeksów'),
 		'ro' => array('' => 'Ieșirea expandată a structurii indecsilor tabelului'),
 		'ja' => array('' => 'テーブルのインデックス構造を拡張表示'),
+		'hr' => array('' => 'Prošireni prikaz indeksa tablice'),
 	);
 }