Avoid accessing the $conf global directly

This can cause errors if the configurations haven't been initialised
yet. On the suggestion of annda, I've added a getConf() method which
will load the configurations if they haven't been already.

types/AbstractBaseType.php

@@ -545,6 +545,18 @@ public function getLang($string)
         return $this->hlp->getLang($string);
     }
 
+    /**
+     * Convenience method to access plugin configurations
+     *
+     * @param string $string
+     * @return string
+     */
+    public function getConf($string)
+    {
+        if (is_null($this->hlp)) $this->hlp = plugin_load('helper', 'struct');
+        return $this->hlp->getConf($string);
+    }
+
     /**
      * With what comparator should dynamic filters filter this type?
      *

types/User.php

@@ -65,7 +65,6 @@ public function handleAjax()
     {
         /** @var AuthPlugin $auth */
         global $auth;
-        global $conf;
         global $INPUT;
         global $_SERVER;
         global $USERINFO;
@@ -76,7 +75,7 @@ public function handleAjax()
 
         if (
             !auth_isMember(
-                $conf['plugin']['struct']['allow_username_autocomplete'],
+                $this->getConf('allow_username_autocomplete'),
                 $_SERVER['REMOTE_USER'],
                 (array) $USERINFO['grps']
             )