Make getUserData return everything if nothing was passed

lib/oauth.php

@@ -133,10 +133,12 @@ class oAuth2{
     exit;
   }
 
-  function getUserData($value){
+  function getUserData($value = null){
+    if(is_null($value))
+      return $this->userData;
     if(isset($this->userData[$value]))
       return $this->userData[$value];
-    return false;
+    return null;
   }
 
   function hasRole($role){