refactor(dart/transform): Correct Dart analyzer warnings

- Fix numerous Dart analyzer warnings we had been ignoring.
- Delete unused `in_progress` dir

modules/angular2/src/transform/transformer.dart

@@ -9,7 +9,6 @@ import 'bind_generator/transformer.dart';
 import 'reflection_remover/transformer.dart';
 import 'template_compiler/transformer.dart';
 import 'common/formatter.dart' as formatter;
-import 'common/names.dart';
 import 'common/options.dart';
 import 'common/options_reader.dart';