update elements and fix some bugs

lib/src/iron-meta/test/iron-meta.html

Index: lib/src/iron-meta/test/iron-meta.html
diff --git a/lib/src/iron-meta/test/iron-meta.html b/lib/src/iron-meta/test/iron-meta.html
index c1a40282ebc8b85429fc38b5582f7fa6e56c652f..c4dc2500d27f959f535616fd5da1a7cead038f9a 100644
--- a/lib/src/iron-meta/test/iron-meta.html
+++ b/lib/src/iron-meta/test/iron-meta.html
@@ -179,6 +179,15 @@ suite('<iron-meta>', function () {
       expect(registeredValue).to.be.equal(secondValue);
     });
   });
+
+  suite('singleton', function () {
+
+    test('only one ironmeta created', function () {
+      var first = Polymer.IronMeta.getIronMeta();
+      var second = Polymer.IronMeta.getIronMeta();
+      expect(first).to.be.equal(second);
+    });
+  });
 });
     </script>