Replace bootstrap logic with 'boot.js', use 'component/dart' mime-type and add

pkg/polymer/test/bind_test.dart

 // Copyright (c) 2013, 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.
 
 import 'dart:async';
 import 'dart:html';
 import 'package:polymer/polymer.dart';
 import 'package:unittest/unittest.dart';
 import 'package:unittest/html_config.dart';
 import 'package:unittest/matcher.dart';
@@ skipping 26 matching lines @@
     expect($['barBool'].attributes, isNot(contains('foo?')));
     expect($['barContent'].innerHtml, foo);
     _testDone.complete();
   }
 
   ready() {
     onMutation($['bindId']).then(_runTest);
   }
 }
 
+@initMethod
 main() {
-  initPolymer();
   useHtmlConfiguration();
 
   setUp(() => Polymer.onReady);
 
   test('ready called', () => (querySelector('x-foo') as XFoo).onTestDone);
 }