WebFingerResource introduced, instead of strict Profile object

This is the beginning of getting notice URI info via WebFinger

*XrdActionLinks is renamed *WebFingerProfileLinks, check EVENTS.txt
in WebFinger plugin for new events.

plugins/WebFinger/lib/webfingerresource.php

@@ -0,0 +1,54 @@
+<?php
+/**
+ * WebFinger resource parent class
+ *
+ * @package   GNUsocial
+ * @author    Mikael Nordfeldth
+ * @copyright 2013 Free Software Foundation, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
+ * @link      http://status.net/
+ */
+
+abstract class WebFingerResource
+{
+    const PROFILEPAGE = 'http://webfinger.net/rel/profile-page';
+
+    protected $identities = array();
+
+    protected $object = null;
+    protected $type   = null;
+
+    public function __construct(Managed_DataObject $object)
+    {
+        $this->object = $object;
+    }
+
+    public function getObject()
+    {
+        if ($this->object === null) {
+            throw new ServerException('Object is not set');
+        }
+        return $this->object;
+    }
+
+    public function getAliases()
+    {
+        $aliases = array();
+
+        // Add the URI as an identity, this is _not_ necessarily an HTTP url
+        $aliases[] = $this->object->getUri();
+
+        try {
+            $aliases[] = $this->object->getUrl();
+        } catch (InvalidUrlException $e) {
+            // getUrl failed because no valid URL could be returned, just ignore it
+        }
+
+        return $aliases;
+    }
+
+    public function updateXRD(XML_XRD $xrd) {
+        $xrd->links[] = new XML_XRD_Element_Link(WebFingerResource::PROFILEPAGE,
+                                        $this->object->getUrl(), 'text/html');
+    }
+}