Enabled CSS tests, added CSS tests to buildbot, fixed tooling with nodejs, and added more tests.

utils/css/cssworld.dart

Index: utils/css/cssworld.dart
diff --git a/utils/css/cssworld.dart b/utils/css/cssworld.dart
index c00422ce4432bda12f1307cfb9bca99ad3a081be..281b2b7b0a54380ad3be6da534d38254cf11fcc3 100644
--- a/utils/css/cssworld.dart
+++ b/utils/css/cssworld.dart
@@ -8,7 +8,7 @@ class CssWorld {
 
   CssWorld(this.classes, this.ids) {
     // Insure no private class names in our CSS world (._foo).
-    for (var aClass in classes) {
+    for (final aClass in classes) {
       if (aClass.startsWith('_')) {
         throw new CssSelectorException(
             "private class ('_' prefix) not valid for CssWorld $aClass)");
@@ -16,7 +16,7 @@ class CssWorld {
     }
 
     // Insure no private element ids in our CSS world (#_foo).
-    for (var id in ids) {
+    for (final id in ids) {
       if (id.startsWith('_')) {
         throw new CssSelectorException(
             "private id ('_' prefix) not valid for CssWorld $id)");