Support browser caching using hashes in serverMode (fixes #93, fixes #92)

test/codegen/expect/server_mode/dev_compiler/runtime/dart_runtime.js

 // Copyright (c) 2015, 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.
 
 var dart;
 (function (dart) {
   var defineProperty = Object.defineProperty;
   var getOwnPropertyDescriptor = Object.getOwnPropertyDescriptor;
   var getOwnPropertyNames = Object.getOwnPropertyNames;
 
@@ skipping 337 matching lines @@
     var init = this[name];
     var result = void 0;
     if (init) result = init.apply(this, arguments);
     return result === void 0 ? this : result;
   };
   // The initializer for dart.Object
   dart.Object.prototype.Object = function() {};
   dart.Object.prototype.constructor = dart.Object;
 
 })(dart || (dart = {}));