create fb:friendpile, a legal-friendly version of fb:facepile

Summary:
as the title says

@naitik, this isn't working and I'm not sure why. Any ideas? I see a 'Tag
FB.XFBML.Friendpile was not found'
error in the console.

Test Plan:
in http://fbrell.com/?server=www.yariv.dev238, entered
<fb:friendpile></fb:friendpile>

DiffCamp Revision: 123657
Reviewed By: naitik
CC: brent, naitik, davidrecordon, achao
Tasks:
#215544: Change "Facepile" name and tag to something else without "Face(s)"

Revert Plan:
OK

src/meta/all.js

@@ -19,6 +19,7 @@
  *   fb.xfbml.element
  *   fb.xfbml.facepile
  *   fb.xfbml.fan
+ *   fb.xfbml.friendpile
  *   fb.xfbml.like
  *   fb.xfbml.likebox
  *   fb.xfbml.livestream

src/xfbml/tags/facepile.js

@@ -15,7 +15,7 @@
  *
  * @provides fb.xfbml.facepile
  * @layer xfbml
- * @requires fb.type fb.xfbml.facepile fb.auth
+ * @requires fb.type fb.auth
  */
 
 /**

src/xfbml/tags/friendpile.js

@@ -0,0 +1,28 @@
+/**
+ * Copyright Facebook Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * @provides fb.xfbml.friendpile
+ * @layer xfbml
+ * @requires fb.type fb.xfbml.facepile
+ */
+
+/**
+ * Implementation for fb:friendpile tag.
+ *
+ * @class FB.XFBML.Friendpile
+ * @extends FB.XFBML.Friendpile
+ * @private
+ */
+FB.subclass('XFBML.Friendpile', 'XFBML.Facepile', null, {});

src/xfbml/xfbml.js

@@ -272,6 +272,7 @@ FB.provide('XFBML', {
     { localName: 'login',           className: 'FB.XFBML.Login'           },
     { localName: 'login-button',    className: 'FB.XFBML.LoginButton'     },
     { localName: 'facepile',        className: 'FB.XFBML.Facepile'        },
+    { localName: 'friendpile',      className: 'FB.XFBML.Friendpile'      },
     { localName: 'name',            className: 'FB.XFBML.Name'            },
     { localName: 'profile-pic',     className: 'FB.XFBML.ProfilePic'      },
     { localName: 'recommendations', className: 'FB.XFBML.Recommendations' },