fix #626, add AMD module format and make it default

lib/js/common/run.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 fs = require('fs');
 var vm = require('vm');
 
 function __load(path) {
   var data = fs.readFileSync(path);
   var script = vm.createScript(data.toString(), path);
   script.runInThisContext();
 }
 
 var args = process.argv.slice(2);
 var argc = args.length;
 
 for (var i = 0; i < argc-1; ++i) {
   __load(args[i]);
 }
 
 var main = vm.createScript(args[argc-1] + '.main()', 'main');
 main.runInThisContext();