Fix compatibility with DW Greebo

Property $lang in plugins starting from Greebo is protected,
so plugins relying on refnotes_localization (namely on
getByPrefix() method) have to provide an accessor for that.

action.php

@@ -17,6 +17,7 @@
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 class action_plugin_refnotes extends DokuWiki_Action_Plugin {
+    use refnotes_localization_plugin;
 
     private $afterParserHandlerDone;
     private $beforeAjaxCallUnknown;

admin.php

@@ -14,6 +14,7 @@
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 class admin_plugin_refnotes extends DokuWiki_Admin_Plugin {
+    use refnotes_localization_plugin;
 
     private $html;
     private $locale;

locale.php

@@ -7,6 +7,18 @@
  * @author     Mykola Ostrovskyy <spambox03@mail.ru>
  */
 
+/**
+ * Plugins that rely on refnotes_localization should use this trait.
+ */
+trait refnotes_localization_plugin {
+    /**
+     *
+     */
+    public function getRawLang() {
+        return $this->lang;
+    }
+}
+
 class refnotes_localization {
 
     private static $instance = NULL;
@@ -69,7 +81,7 @@ public function getByPrefix($prefix, $strip = true) {
 
         $result = array();
 
-        foreach ($this->plugin->lang as $key => $value) {
+        foreach ($this->plugin->getRawLang() as $key => $value) {
             if (preg_match($pattern, $key, $match) == 1) {
                 $result[$match[1]] = $value;
             }

syntax/references.php

@@ -16,6 +16,7 @@
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 class syntax_plugin_refnotes_references extends DokuWiki_Syntax_Plugin {
+    use refnotes_localization_plugin;
 
     private $mode;
     private $entryPattern;