Be more strict about attributes in sky-binder.

sky/framework/sky-element/sky-binder.sky

Index: sky/framework/sky-element/sky-binder.sky
diff --git a/sky/framework/sky-element/sky-binder.sky b/sky/framework/sky-element/sky-binder.sky
index b7ae88cabb650ace061f231dcaff2dbf27cadc8a..5a57d724832a57b716b8344038e2df3730988d4b 100644
--- a/sky/framework/sky-element/sky-binder.sky
+++ b/sky/framework/sky-element/sky-binder.sky
@@ -27,12 +27,6 @@ class TemplateInstance {
 var emptyInstance = new TemplateInstance();
 var directiveCache = new WeakMap();
 
-(function() {
-  var templateRegistration = registry.registerElement('template');
-  templateRegistration.defineAttribute('if', 'string');
-  templateRegistration.defineAttribute('repeat', 'string');
-})();
-
 function createInstance(template, model) {
   var content = template.content;
   if (!content.firstChild)