fix(change_detect): Sort DirectiveMetadata properties during processing

The Angular 2 render compiler can get out of sync between its transformer
execution and its runtime execution, leading to incorrect change detectors with
out-of-order property values. Stable sorting solves this problem (temporarily).

modules/angular2/src/facade/lang.dart

@@ -97,6 +97,8 @@ class StringWrapper {
   static bool contains(String s, String substr) {
     return s.contains(substr);
   }
+
+  static int compare(String a, String b) => a.compareTo(b);
 }
 
 class StringJoiner {