fix a few things, add comments for others

www/common/userObject.js

@@ -109,7 +109,9 @@ define([
         };
         exp.isFolderEmpty = function (element) {
             if (!isFolder(element)) { return false; }
+            // if the folder contains nothing, it's empty
             if (Object.keys(element).length === 0) { return true; }
+            // or if it contains one thing and that thing is metadata
             if (Object.keys(element).length === 1 && isFolderData(element[Object.keys(element)[0]])) { return true; }
             return false;
         };