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/adminer.js.php

@@ -23,5 +23,6 @@ class AdminerDotJs extends Adminer\Plugin {
 		'pl' => array('' => 'Wczytuj adminer.js'),
 		'ro' => array('' => 'Încarcă adminer.js'),
 		'ja' => array('' => 'adminer.js を読込み'),
+		'hr' => array('' => 'Učitava adminer.js'),
 	);
 }