Add art and thumb url to plexapi collections

lib/plexapi/library.py

@@ -1092,6 +1092,7 @@ class Collections(PlexObject):
     def _loadData(self, data):
         self.ratingKey = utils.cast(int, data.attrib.get('ratingKey'))
         self._details_key = "/library/metadata/%s%s" % (self.ratingKey, self._include)
+        self.art = data.attrib.get('art')
         self.contentRating = data.attrib.get('contentRating')
         self.guid = data.attrib.get('guid')
         self.key = data.attrib.get('key')
@@ -1118,6 +1119,16 @@ class Collections(PlexObject):
     def children(self):
         return self.fetchItems(self.key)
 
+    @property
+    def thumbUrl(self):
+        """ Return the thumbnail url for the collection."""
+        return self._server.url(self.thumb, includeToken=True) if self.thumb else None
+
+    @property
+    def artUrl(self):
+        """ Return the art url for the collection."""
+        return self._server.url(self.art, includeToken=True) if self.art else None
+
     def __len__(self):
         return self.childCount