Remove generated directories with 100s of files.

client/html/generated/html/interface/CSSImportRule.dart

Index: client/html/generated/html/interface/CSSImportRule.dart
diff --git a/client/html/generated/html/interface/CSSImportRule.dart b/client/html/generated/html/interface/CSSImportRule.dart
deleted file mode 100644
index de46f87741046271966cae4f57f94381c32e13a0..0000000000000000000000000000000000000000
--- a/client/html/generated/html/interface/CSSImportRule.dart
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// WARNING: Do not edit - generated code.
-
-interface CSSImportRule extends CSSRule {
-
-  final String href;
-
-  final MediaList media;
-
-  final CSSStyleSheet styleSheet;
-}