add tag attribute to photo object.

Author: blacktwin

plexapi/photo.py

@@ -117,6 +117,7 @@ def _loadData(self, data):
         self.updatedAt = utils.toDatetime(data.attrib.get('updatedAt'))
         self.year = utils.cast(int, data.attrib.get('year'))
         self.media = self.findItems(data, media.Media)
+        self.tag = self.findItems(data, media.Tag)
 
     def photoalbum(self):
         """ Return this photo's :class:`~plexapi.photo.Photoalbum`. """