old_contents: var Person = require('./lib/person');
  var url = 'http://neo4j.ynu.edu.cn';
  var na = new Person(null, url);
  
  na.create('na57', 'na57 person', function (err, result) {
  	console.log('done');
  });
  
  var ex = new Person(21, url);
  ex.delete(function () {
  	console.log('deleted');
  });
new_contents: var Concept = require('./lib/concept');
  var ConceptManager = require('./lib/concept-manager');
  var Middleware = require('./lib/concept-middleware');
  
  module.exports = {
  	Concept: Concept,
  	ConceptManager: ConceptManager,
  	Middleware: Middleware
  };
subject: update index.js