#16 新增createEntityAsync方法

修复entity.id为null

demo/libs/framework/framework.d.ts

@@ -370,6 +370,7 @@ declare module es {
         getPostProcessor<T extends PostProcessor>(type: any): T;
         removePostProcessor(postProcessor: PostProcessor): void;
         createEntity(name: string): Entity;
+        createEntityAsync(name: string): Promise<Entity>;
         addEntity(entity: Entity): Entity;
         destroyAllEntities(): void;
         findEntity(name: string): Entity;